Abstract: To study the optimum conditions for the fermentation of Trichoderma asperellum,the effects of dry weight and spores number on mycelia were optimized by single factor orthogonal experiment. Experimental result showed that the best medium was soy flour medium and the optimum conditions were as follows:0.25% of Soy flour,0.3% of KH₂PO₄,0.15% of MgSO₄,8×10⁶/mL of inoculationamount,100 mL/250 mL of bottling volume,1.35% of Peptone,3.5% of glucose,160 r/min of rotating speed,25 ℃,natural light,and primary pH7.The fermentation conditions can make the dry weight of Trichoderma viride reach 19.453 g/L,the number of spores reached 4.4812×10⁹/mL. For the mass production of Trichoderma asperellum reduced the cost,shorten the fermentation cycle,laying the theoretical basis for the industrial production of Trichoderma asperellum.