In this study, silk fibroin powder was treated by dielectric barrier discharge (DBD) plasma. The objective is to improve the performance of the silk fibroin powder/polyurethane (PU) blend film used in biomechanical field. The scanning electron microscope (SEM) showed that the plasma-treated powder was broken into small particles and the film from the treated powder became homogeneous and dense. Fourier transform infrared spectroscopy (FTIR) revealed that the hydrophobic groups in silk fibroin powder were oxidized during plasma treatment. Little change in chemical composition was found on the surface of the blend film from plasma-treated powder. The fracture strain of the blend film from plasma-treated powder was remarkably raised, whereas its tensile strength was influenced significantly by the plasma treatment conditions. The wet-out time of the plasma-treated powder/PU film was shortened considerably. This indicates the improved hydrophilicity of the blend film. In addition, the decreased values of water vapor permeability suggested that the structure of the blend film became dense. This might result from the strong interfacial adhesion between plasma-treated powder and PU. POLYM. ENG. SCI., 50:1705-1712, 2010. (C) 2010 Society of Plastics Engineers