The protoplast of Trichoderma virid CICC13038 was mutated using Nd:YAG laser of 266 nm light.And a high-cellulase producing strain JG13 was bred by screening with cellulose microcrystalline.Under the condition of 28°C

180 rpm and 72 h of fermentation time

optimal conditions for the celluase ferment by orthogonal experiment were:2% bran as the carbon source

1% (NH 4) 2 SO 4 as the nitrogen source

0.5% Tween-80 as a enzyme-promoting agent

and 25 mL of medium volume in a 250 mL bottle.The cellulase activity of the mutant reached 35.68 U/mL

25.76% higher than that of the original strain under the same conditions.The mutant JG13 has a great potential in industrial production.And it also can be used as the original strain for further mutagenesis to get the strain of higher cellulase activity.