Cellulase was produced by growing Penicillium sp. NXP25 in liquid medium consisted of 5% com cob powder, 3% wheat bran, 0.35% nitrogen source No 10 and 0.3% calcium chloride. The optimum culture conditions were initial pH 5.0, 10% mycelial inoculum, temperature 29℃, shaking speed 280r/min and cultivation time 72h. When determining enzyme activity at 50℃, endo-1, 4-?-glucanase activity, extro-1, 4-?-glucanase activity, ?-glucosidase activity and filter paper enzyme activity of the supernatant of the culture were 841u/mL, 13u/mL, 24u/mL and 46u/mL, respectively. The optimum pH and temperature for the action of the above enzymes were pH 4.8 and60℃, pH5.0 and 50℃, pH 4.5 and 70℃, pH 5.0 and 55℃, respectively. Stable pH range of the above enzymes were 3.0-7.0, 4.0~6.0, 4.0~7.0 and 4.0~6.0, respectively. After incubating the enzyme complex at 65C for 30min, 24% of endo-1, 4-?-glucanase activity, 7% of extro-1, 4-?-glucanase activity, 89%of ?-glucosidase activity and 8% of filter paper enzyme activity were remained, respctively.