Cellulase-excreted filamentous fungi Penicillium sp.FS010441 with higher cellulase activities, isolated from the deep sea mud of Huanghai, was.studied. The production of enzyme and properties of the cellulase excreted were further studied.The optimal and highest growth temperature were 15℃ and 37℃ respectively, and it could also grow under 4℃. The optimal temperature and optimal pH for the cellulase were 50℃ and 4.2 respectively.The enzyme activity was higher and more stable between 40~55℃.