1. A method for reconstructing a three-dimensional object, comprising: acquiring two-dimensional line drawing information of the three-dimensional object, wherein the two-dimensional line drawing information comprises a two-dimensional line drawing; segmenting, according to the two-dimensional line drawing information and according to a degree of freedom, the two-dimensional line drawing to obtain at least one line sub-drawing, wherein the degree of freedom is a smallest quantity of vertices that need to be known for determining a spatial location of the three-dimensional object that comprises planes; reconstructing a three-dimensional sub-object according to the line sub-drawing; and combining all three-dimensional sub-objects to obtain the three-dimensional object.