Abstract: The polyurethane (PU) membranes modified with silk fibroin(SF),made from SF protein and liquid prepolymer with terminal\|isocyanate groups,were obtained by the process of prepolymer having reaction on the surface of SF membranes and then controlling the moisture of system and the solution conditions.Analized the surface properties of membrane by SEM\,ATR\|FTIR and X\|ray energy spectrometer.The results showed that SF was grafted onto the surface of PU membranes;PU membranes modified with SF have good flexibility as well as their hydrophilicity was improved,and certain water vapor permeability.