Abstract: In order to overcome multi-path effect for phase measuring profilometry, aphase fusion algorithm is proposed.First, we build a mathematical model for the multi-path effect, and then we analyze the multi-path-effect-caused phase error via the model.Second, we find that the phase error caused by the multi-path effect is mainly raised in the area where the reflectivity dramatically varies; and for a pixel, besides the true phase values and the true reflectivity of the pixel's neighbors, the multi-path effect is also with regard to scanning direction.Finally, aphase fusion algorithm is derived based on the previous analysis, i.e., two groups of phase values are obtained by scanning a target along Xdirection and Ydirection respectively, and then the two groups of phase values are fused by employing the corresponding reflectivity of the target.Thus the phase error is corrected.The experimental results demonstrate that such kind of phase error always exists and is not ignorable even if the number of projected patterns is increased, and, with the proposed method, phase error can be effectively reduced by 2 times.