1. A method for reproducing single object in motion in a 3D scene, comprising: simultaneously acquiring at least two channels of video stream data in real time at different angles for single object to be displayed; recognizing a shape of the single object varying in real time from the at least two channels of video stream data; obtaining corresponding object motion trajectory according to the shape of the single object varying in real time; and processing the shape of the single object varying in real time and the corresponding object motion trajectory into a 3D image and superposition-displaying the 3D image on the 3D scene in real time; wherein the recognizing a shape of the single object varying in real time from the at least two channels of video stream data comprises: performing a sampling processing of each of the at least two channels of video stream data to obtain video image data sampled each time; judging whether the video image data contain an single object, and if so, performing a binarization processing of the video image data to extract single object contour information; recognizing a shape of the single object corresponding to the single object contour information from a preset single object model database; and synthetizing shapes of the single object recognized after each sampling of respective channels of video stream data to obtain a shape of the single object varying in real time; wherein the obtaining corresponding object motion trajectory according to the shape of the single object varying in real time comprises: obtaining relative spatial position information of the shape of the single object varying in real time; obtaining variation information of a determined contact on the shape of the single object varying in real time, according to the contact on the shape of the single object varying in real time, wherein the contact is a characteristic key point for identifying the single object; and obtaining corresponding object motion trajectory from a preset motion trajectory database, according to the relative spatial position information and the variation information of the contact; and wherein, the obtaining relative spatial position information of the shape of the single object varying in real time comprises: obtaining angle information with the shape of the single object varied, from video image information of the at least two channels of video data streams; sensing distance information of the single object in real time through a distance sensor; and obtaining the relative spatial position information of the single object according to the angle information with the shape of the single object varied and the distance information of the single object.