A novel and high precise three-dimensional (3D) reconstructed method of big scale objects is proposed. The sub-shapes of the experimental object are measured with phase measuring profilometry (PMP),height matching is carried out in the modulation maximum area with an algorithm due to maximum correlativity. The method saves matching time by computer compared to using the whole height data of the sub-objects,and the mosaic precision is improved. Finally the whole shape of objects is obtained by the mosaic method. Binarization templates of modulation are generated in order to draw out the object from background and shadow,and image mosaic is carried out by using the overlapping position obtained from the above height matching. The results show that the repeatability precision of our method is superior to 20 μm,and the mosaic precision is beyond100 μm,which is an effective method to reconstruct big scale objects.