Abstract: The physicochemical properties of Calcium Phosphate Cement (CPC) were improved by adding in silk fibroin of varied character. The structure of the materials was investigated by X-ray diffraction and Fourier transform infrared spectroscopy. The surface morphology was observed by Scanning Electron Microscope. The porosity of the material was measured by drainage method. The mechanical properties were tested by Instron Universal Testing Machine. The results showed that the products of hardening reaction of CPC with silk fibroin of varied character added were similar to those of pure CPC as hydroxyapatite was produced in both reactions. Silk fibroin of varied character significantly improved the flexural strength of CPC. The character of the silk fibroin had distinct effects on the work-of-fracture, the work-of-fracture of CPC with silk fibers increased significantly, which was 7~21.8 times of that of pure CPC. The character of the silk fibroin had no significant effects on the structure of the materials, but the porosity decreased.