Strain X-5 which with high cellulos-producing activity was obtained and identified to be Fungi Imperfecti, Moniliales, Moniliaceace, Aspergilleae,Penicillium.. Production of cellulase was carried out by submerged fermentation with strain X-5. The results showed that the best carbon source, nitrogen source, medium volume, inoculum size, temperature, the initial pH value and culturing time were 5.0% rice straw powder, 3.0% bean cake meal, 60mL, 5.0%, 26~28 ℃, 4.5~6.0, and 120 h, respectively. Under the above conditions, the highest activities of CMCase and FPase in the fermented broth were 75.72 IU /ml and 6.68 IU/mL, respectively.