The aqueous solution of the silk fibroin from silkworm Bombyx mori cocoons was obtained by treatment of the neutral salt (CaCl₂). Peroxidase(POD)was immobilized in the silk fibroin membrane. Activity and characteristics of the POD-immobilized fibroin membrane were analysed.The results show that the activity of the POD-immobilized membrane is high;Optimum pH range for the enzyme membrane,being at pH5.0-7.0,was widened in comparison with the free enzyme;and its thermal stability was good.