A series of porous silk fibroin materials were prepared by freezing fibroin aqueous solution at –18 °C for 10 days. The process required no freeze-drying, chemical cross-linking, or the aid of other polymeric materials. X-ray powder diffraction patterns from the porous silk materials displayed features of crystal of metastable silk I polymorph. By adjusting the preparation conditions, silk I porous materials with average pore diameter of 30-240 μm and porosity of 70 -95 % can be prepared. The silk I porous materials were embedded in hypodermis on the dorsal surface of SD white rats, resulting that all rats survived with good general condition, and silk I porous materials were degraded and absorbed mostly in 6 weeks.