Abstract: Polystyrene (PS) membranes with pits of different sizes were presented by liquid phase separation，and then convex chitosan membranes were prepared with the PS membranes as templates. The surface morphology and structure were characterized by using scanning electron microscope，atomic force microscope，and the formation mechanism of membrane with pore structure was proposed. By changing the parameters，such as the volume ratio of glycerol (Gly) and propylene glycol (PG)，the temperature of film formation and the rate of evaporation，the membranes with different surface morphologies and microstructures could be obtained. The PS films patterned with concavities were used as templates to fabricate convex patterned chitosan membranes. The sizes of the convexes were determined as about 1～50 μm by scanning electron microscope and atomic force microscope. And the air-water contact angles decreased with the increase of convex size. It could be the biomaterial basis for studying the biological function of cells with different surface convexes.