In order to reconstruct the three-dimensional online shape of large object, a scheme combining stitching based on the improved Stoilov algorithm is presented. It involves two methods. The first method is that the deformed grating fringe is performed image mosaic at first, and then it is reconstructed by Stoilov algorithm. The second method is that three-dimensional construction is performed to multi-group of grating fringe respectively, and then contour mosaic is performed. Experimental results show that the two methods have better three-dimensional reconstruction capability to large objects and both have advantages and disadvantages.