Abstract: With laser beam directly radiated to the test surface, a CCD was used to pick up the fringes before and after its deformation due to speckle interference. These fringes were translated into the displacement and deformation components and its off surface displacement was obtained. In the optimized algorithm, phase shift technology was adopted to obtain the fringe image of another shift, which separated surface displacement with off surface displacement, the zero order component was removed and projection grating was move by a half period. A three-dimension space model was established through Matlab and four step phase algorithm. The experiment data indicated this solution could measure the three dimension deformation of the object accurately.