In this work, strain Phanerochaete chrysosporium producing cellulase was studied by fermentation process. Carbon source involves cellobiose, xylose, xylan, carboxymethylcellulose sodium, avicel, filter paper, corn stalk and glucose. Peptone, yeastextract, carbamide, ammonium nitrate, ammonium sulfate were researched for nitrogen source. Under the conditions of carbon source avicel, nitrogen source ammonium, the activity assays on different enzymes of respective component is optimum. Ultraviolet ray, nitrosoguanidine were applied to mutate Phanerochaete chrysosporium. The optimal conditions were as follow: 60S, 50min.Colony morphology with obvious variation was used as sceening index. 120mutants were selected, carboxymethyl cellulose activity of cach mutant was determined and 20 strains with 30% increasing of cellulose activity were screened.GD3 mutant was obtained, with the increasing rate of filter paper activity 30.50%.