The invention discloses a structured light measuring system calibration method based on sinusoidal grating. The method includes producing coding grating, setting up measuring system to capture calibrating board flat images, projecting coding grating, collecting, storing, confirming phase-unfolding initial points, solving wrapped phase and unfolding, restoring the calibrating board flat images of projector imaging planes, calibrating projectors according to the multi-group projector calibrating board flat images at different positions, calibrating cameras according to multiple camera calibrating board flat images at different positions, and acquiring rotation matrixes from projector coordinate systems to camera coordinate system according to calibrating results of the projectors and the cameras. The phase-unfolding initial point can be effectively confirmed by utilizing coding disc images, and image quality of image region is guaranteed to be high; and the designed phase-unfolding method has a noise-proof function, 'line-pulling' conditions in conventional phase-unfolding methods are overcome, and the designed structured light measuring system calibration method has the advantages of simple operation, strong robustness, high measurement accuracy and the like.