Abstract: The immobilization of lipase is helpful to lowering the cost of application of lipase.A special microstructure in the CA/PTFE composite membrane was proposed to immobilize Candida rugosa lipases.Firstly，the composite membrane was prepared through coating hydrophilic CA membrane with nanometer-sized pores on the hydrophobic PTFE membrane with micrometer-sized pores.By ultrafiltration of the enzyme solution，lipase was retained by the CA dense layer and was located on pores of PTFE layers and at the interface of CA and PTFE layers.SEM photos showed that most of immobilized lipase was located on the interface of composite membrane.Then immobilized enzyme membranes were used in biphasic enzyme membrane reactor（BEMR）for hydrolysis of olive oil.The effects of the thickness of CA layer and the lipase loading density on membrane bioreactor performance were investigated.Experimental results showed that the special microstructure in composite membrane could efficiently immobilize the lipase，and the maximum specific activity（1.24 μmol FFA·min^-1·cm^-2）was found to be higher than the value reported in literatures.The immobilized enzyme membrane was used for 10 times（5 h/times）with only 20% activity lost.