Using the freeze-drying method, Nano-TiO2/silk fibroin porous films were synthesized with different ratios of TiO2 to silk fibroin solution. Through scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile strain, and water-solubility tests, the structures and properties of these porous films were characterized. The SEM results indicated that the pores of the nano-TiO2/silk fibroin porous films were uniformly distributed by the freeze-drying method. The XRD analysis indicated that the formation of nano-TiO2 particles might induce a conformational transition of silk fibroin from the typical Silk I to the typical Silk II structure partly with an increase in the crystallinity of the porous films. Compared with the pure silk fibroin porous films, the mechanical properties of nano-TiO2/silk fibroin porous films were improved, and its heat transition temperature was also enhanced; however, the water-solubility of this material was diminished. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 468-472, 2010