the present invention will be further described in detail below in combination with an embodiment . a telescopic hose is shown in fig1 . a pipe wall of the telescopic hose 10 is formed by a plurality of wrinkling parts 11 coiled in a stretching direction d 1 of the telescopic hose 10 . drawn in fig1 are a folded section 20 and a stretching section 30 of the telescopic hose 10 . coiling indicates that the wrinkling parts 11 extend clockwise or anticlockwise ( namely coiling direction d 2 ) around a center line which is the stretching direction d 1 . an extending direction of the wrinkling parts 11 around the center line is a coiling direction , and the coiling direction is also the processing direction of the telescopic hose 10 . finally , the pipe wall of the telescopic hose 10 forms a helical structure similar to a spring or a bolt . each wrinkling part 11 includes a first wrinkling wall 100 and a second wrinkling wall 200 , as shown in fig2 and fig3 . for brief description in fig2 , fig3 , and fig4 , the thickness of the pipe wall is concealed , and only lines are reserved . both the first wrinkling wall 100 and the second wrinkling wall 200 extend along the coiling direction of the wrinkling part 11 . the wrinkling part 11 protrudes far from an outer side of the telescopic hose 10 . that is , the fracture surface of the wrinkling part 11 is in a crest shape when being seen from a section of the wrinkling part 11 in an extending direction d 3 . the peak of the crest is the protruding direction of the wrinkling part 11 , and the first wrinkling wall 100 and the second wrinkling wall 200 are respectively positioned on two sides of the protruding direction of the wrinkling part 11 . along the coiling direction of the wrinkling part 11 , one side of the first wrinkling wall 100 is connected with the second wrinkling wall 200 , and the other side of the first wrinkling wall 100 is connected with the second wrinkling wall of an adjacent wrinkling part 12 . the section of the first wrinkling wall 100 along the extending direction d 3 of the wrinkling part 11 includes a bottom concave section 101 , a first connecting section 102 , a second connecting section 103 , and a top concave section 104 . the bottom concave section 101 , the first connecting section 102 , the second connecting section 103 , and the top concave section 104 are connected end to end from one side of the first wrinkling wall 100 close to the adjacent wrinkling part 12 to the side of the first wrinkling wall 100 close to the second wrinkling wall 200 . bottoms of both the top concave section 104 and the bottom concave section 101 protrude opposite to the protruding direction of the wrinkling part 11 . the top concave section 104 and the bottom concave section 101 form two grooves along the coiling direction , wherein the top concave section 104 is positioned close to the crest peak of the wrinkling part 11 , and the bottom concave section 101 is positioned at the bottom of the trough of the wrinkling part 11 . in an extending or folding process of the telescopic hose , both the top concave section 104 and the bottom concave section 101 can be bent to ensure that the wrinkling parts 11 of the telescopic hose can be superposed together . the first wrinkling wall 100 further includes a raised section 105 between the top concave section 104 and the second connecting section 103 , and two ends of the raised section 105 are respectively connected with the top concave section 104 and the second connecting section 103 . the raised section 105 forms a raised edge along the coiling direction , so that the first wrinkling wall 100 can be conveniently bent and approach the second wrinkling wall 200 . the first connecting section 102 protrudes towards an outer side of the wrinkling part 11 . the second connecting section 103 is sunken towards an inner side of the wrinkling part 11 . the first connecting section 102 and the second connecting section 103 are respectively used for keeping a folded state and an extended state of the telescopic hose . the first connecting section 102 protrudes towards the outer side to keep the shape of the hose in the extended state , and the second connecting section 103 is sunken towards the inner side to keep the shape of the hose in the folded state . a section of the second wrinkling wall 200 along the extending direction d 3 of the wrinkling part 11 includes a third connecting section 201 . the third connecting section 201 is sunken towards the inner side of the wrinkling part 11 , so that the current shape of the third connecting section 201 is kept unchanged in the extending and folding processes of the hose . the pipe wall of the telescopic hose 10 further includes at least two columns of through holes 300 ( only one column is drawn in the figure ), preferably , four columns or six columns of through holes 300 ; and each column of through holes 300 is arranged along the stretching direction d 1 of the telescopic hose 10 . water flow or water in the soil enters the inner cavity of the hose via the through holes 300 . when the telescopic hose 10 is in the folded state , the through holes are uniformly arranged around the telescopic hose 10 at intervals . the through holes 300 are arranged linearly in the stretching direction d 1 of the telescopic hose 10 . when the hose is in the extended state , each wrinkling part 11 rotates for a relatively small angle along the coiling direction in the extending process , so each column of through holes 300 is helically arranged on the circumference of the pipe wall of the hose in the extended state . the through holes 300 are positioned at joints of the first wrinkling walls 100 and the second wrinkling walls 200 to facilitate processing . the section of the first wrinkling wall 100 along the extending direction d 3 of the wrinkling part 11 further includes a superposed section 106 ; one end of the superposed section 106 is connected with the second connecting section 103 , and the other end of the superposed section 106 is connected with the raised section 105 . the superposed section 106 includes a first superposed section 1061 and a second superposed section 1062 . the first superposed section is an extension of the second connecting section 103 , and the second superposed section 1062 is an extension of the raised section 105 . the second superposed section 1062 is positioned on the outer side of the wrinkling part 11 relative to the first superposed section 1061 . the first superposed section 1061 extends from the second connecting section 103 to the third connecting section 201 along an inner surface of the wrinkling part 11 . in another embodiment , the first superposed section 1061 may also extend to a position nearby the bottom groove 101 along the third connecting section 201 all the time , to further improve the strength of the second wrinkling wall 200 . moreover , as another optional structure , the second superposed section 1062 may extend to the tail end of the first connecting section 102 connected with the bottom concave section 101 along the outer surface of the second connecting section 103 . the superposed section 106 has a structure formed by superposing two plastic or resin sheets extending along the coiling direction . the superposed section 106 may enhance the structural strength of the top concave section 104 , the extending part of the first superposed section 1061 may enhance the structural strength of the third connecting section 201 , and the extending part of the second superposed section 1062 may enhance the structural strength of the second wrinkling wall 200 , so that the original shapes of the top concave section 104 and the third connecting section 201 may be kept in the folding and extending processes . the section of the second wrinkling wall 200 along the extending direction d 3 of the wrinkling part 11 further includes a fourth connecting section 202 . the fourth connecting section 202 is positioned at one end of the third connecting section 201 far from the joint of the first wrinkling wall 100 and the second wrinkling wall 200 , and one end of the fourth connecting section 202 is connected with the third connecting section 201 . the fourth connecting section 202 protrudes towards the outer side of the wrinkling part 11 . the fourth connecting section 202 may be slightly bent towards the inner side of the wrinkling part 11 during folding to facilitate the folding . the second connecting section 103 is as long as or at least slightly longer than the first connecting section 102 . the bottom of the top concave section 104 faces one side of the protruding direction of the wrinkling part 11 . moreover , the telescopic hose 10 further includes gauze around the outer side of the pipe wall of the telescopic hose 10 . the gauze may prevent soil or other impurities from passing and prevent the hose from being blocked . the telescopic hose has the folded state and the extended state . when the telescopic hose 10 is contracted to the folded state , the two ends of the bottom concave section 101 are bent and contracted towards the center , and the two ends of the top concave section 104 are expanded far from the center of the top concave section 104 . the raised section 105 is bent towards the inner side of the telescopic hose 10 at the same time . thus , the part between the raised section 105 and the bottom concave section 101 rotates towards the second wrinkling wall 200 by taking the protruding vertex of the raised section 105 as the center when folded and contracted , till the first wrinkling wall 100 is attached to the second wrinkling wall 200 to form the folded state . further , the section of the first wrinkling wall 100 along the extending direction d 3 of the wrinkling part 11 is a curve . as shown in fig4 , the linear distance from one end of the curve to the other end is c . that is , the bottom center of the bottom concave section 101 is a point o 1 , and the point of the joint of the first wrinkling wall 100 and the second wrinkling wall 200 on the section is a point o 2 , so the distance between the point o 1 and the point o 2 is c . the point of the joint of the first wrinkling wall and the second wrinkling wall of the adjacent wrinkling part 12 on the section is a point o 3 , and the linear distance between the point o 2 and the point o 3 is a . further , the straight line passing through the point o 1 and the point o 2 is l 1 , the straight line passing through the point o 1 and the point o 3 is l 2 , and the included angle between l 1 and l 2 is a . the straight line along the tangential direction of the first connecting section 102 connected with one end of the bottom concave section 101 is l 3 , the straight line along the tangential direction of the fourth connecting section 202 connected with the other end of the bottom concave section 101 is l 4 , and the included angle between l 3 and l 4 is β . the impression distance of the top concave section 104 , that is the distance between the bottom center of the top concave section 104 and the point o 2 is h . the impression distance of the bottom concave section 101 , that is the distance between the tail end point of the extending part of the first superposed section 1061 extending along the inner surface of the second wrinkling wall 200 and the bottom midpoint of the bottom concave section 101 ( or the bottom of the bottom concave section 101 at the trough of the wrinkling part 11 ) is e . then the dimension of the telescopic hose 10 is : h = 0 - 4 mm , when h = 0 , the top concave section 104 is positioned right above the top of the crest of the wrinkling part 11 ; e = 0 - 5 mm , when e = 0 , the first superposed section 1061 extends along the inner surface of the second wrinkling wall 200 all the time to reach the bottom center of the bottom concave section 101 . the above dimension data is under the condition that the orifice diameter of the telescopic hose is 2 to 8 inches , wherein the orifice diameter may be the inside diameter or the outside diameter of the hose . further , the optional dimensions of the telescopic hose 10 under different orifice diameters are listed in table 1 below . it should be pointed out that , the dimensions recorded in the above table are preferred items , but it does not mean that the telescopic hose recorded in this embodiment can only select the data in the above table , and any other dimensions in accordance with the dimension of the hose of this embodiment is optional . the telescopic hose obtained by the above embodiment is compared with some telescopic hoses available in the market , and the results are shown in table 2 below : to sum up , the hose according to the embodiment of the invention can be extended or folded conveniently , and can be stably kept in an extending or folded state . in the extended state , the hose presents an appearance similar to helixes ; while in the folded state , the hose is folded into a straight pipe , and the length of the hose is greatly shortened , so that the storage space required during transportation is reduced and the transportation cost is reduced . moreover , the hose is generally applied to soil improvement or courtyard greening and the like . the overall extension and contraction rate of the hose is less influenced by the material , so the service life is long , the using cost is reduced , and environmental friendliness is facilitated . the hose is universally popularized and used in the fields of landscaping and soil improvement at home and abroad , and the social response is good . further , both the top concave section and the bottom concave section of the first wrinkling part have a bent structure similar to the shape of s , so that the bending amplitude of the pipe wall is reduced , breakage caused by excessive bending of the pipe wall may be effectively prevented . particularly when the material is aged , the situation of pipe wall breakage caused by the increase of material brittleness due to ageing may be reduced , and the service life of the hose may be prolonged . in conclusion , the above embodiment is merely a preferred embodiment of the present invention , and equivalent alterations and modifications made according to the patent scope of the present invention shall fall into the scope of the present invention .