Abstract: PVA/Chitosan(CS) composite membrane was used for enzyme processing of fats and oils. The concentration of lipase and cross-linking agent which influence the immobilization of lipase in membrane were determined. Epichlorohydrin is used as the cross-linking agent. The immobilized lipase is 0.66 u·cm -2 and the recovery of immobilized lipase is 24%. The membrane reactor was tested to synthesis monoglyceride(MG), which could be used many times without loss conversion yield of MG. The PVA/CS lipase membrane reactor is a new reactor for lipase catalytic biphase systems.