1. A stereoscopic vision three dimensional measurement method for calculating a laser speckle as a texture, comprising: simulating a forming process of a laser speckle first, and performing calculation to obtain a digitized laser speckle diagram; then outputting the laser speckle diagram onto a film or a photographic dry plate; projecting the laser speckle diagram on the film or the photographic dry plate to a surface of a measured object subsequently; acquiring a left view and a right view of the measured object finally, then finding all matching points corresponding to each other of the surface of the measured object in the left view and the right view, and reconstructing a three dimensional point cloud of the surface of the measured object according to parallax data of the matching points; wherein the “performing the calculation to obtain the digitized laser speckle diagram” comprises: simulating scattering of coherent lights by a rough surface to form a plurality of beams of scattered lights; and transmitting the plurality of beams of scattered lights onto an observation plane to perform coherent superposition so as to form the laser speckle diagram; wherein a light intensity value of each point on the observation plane is obtained through numerical calculation.