A microporous poly(vinyl alcohol)/Starch composite polymer membrane was successfully synthesized by a biodegradation method. Effects of different poly(vinyl alcohol)/Starch compositions on the porous structures of the porous polymer membranes were further investigated in detail. The characteristic properties of PVA/ Starch composite polymer membranes were systematically studied by scanning electron microscopy (SEM), SL200B angle of contact instrument and Sturm test. The result shows the formation of 1μm-10μm microporous in the blend polymer membrane, which strongly depended on the content of starch in the blend. This method is convenient and will greatly promote the practical application of porous polymer membranes in various areas.