One of key technologies for the manufacture of membrane mirrors is its surface shape control. The structure and function of a surface shape control system which is developed by our laboratory based on fuzzy logic control theory are described in detail. The surface shape control of membrane mirror under uniform load previously has been theoretically analyzed and simulated. Here a non-uniform load method is analyzed and simulated for the surface shape control of a membrane mirror with 300 mm aperture and different F numbers. The results of the simulation show that the RMS wavefront error of the membrane mirror under non-uniform load can be controlled and improved in two orders of magnitude compared with that of the membrane mirror under uniform load.