The effect of media components on filter paper activity of Thielavia terrestris( ATCC38088) was studied through single factor experiments,including different carbon sources( CMC-Na,Avicel,filter paper,straw powder,wheat bran,soluble starch,glucose),different nitrogen sources( beef extract,peptone,ammonium chloride, soybean meal,yeast extract,ammonium sulfate) and different initial pH value from 3.0 to 6.0.Based on the results of single factor experiments,liquid fermentation conditions for cellulase production of the strain were optimized through orthogonal test.The results showed that the optimum conditions were as follows: concentrations of straw powder and soybean meal were 2.5% and 2.0%,respectively.The initial pH value was 4.0.Under these conditions, the filter paper activity of the strain fermented at 45 ℃ for 48 h reached 1.39 U/mL.