With the development of projectors, the display quality has been widely concerned. The luminance uniformity is a common problem in projection display. Most images with high gray value tend to saturate after uniformity correction, while the common clipping method will decrease the uniformity greatly. In order to solve this problem, a photometric model based on projector-camera system was set up, and then a robust nonlinear algorithm for luminance uniformity correction was proposed on the basis of the traditional linear mapping method. The experimental results indicate that the display luminance of the projector is decreased by 50% from center to edge, corresponding to the relative root mean square (RRMS) error of luminance uniformity of 17.7%. After luminance correction, the RRMS value of saturated images decreases to 1.69%, almost as good as that for nonsaturated images (1.55%), while the average luminance level is well preserved in general.