Abstract: The enzyme production of Bacillus T_7.0,Aspergillus niger Z₃⁴,and Trichoderma reesei,as well as the multi fermentation of these three strains were studied to explore the effect of inoculation sequence and proportion on the enzyme activity.Corn stalks were preprocessed by Candida lipolytica with optimization of pretreatment conditions,using CMC enzyme activity and FPA enzyme activity as index. The results showed that Bacillus T_7.0 should be inoculated 12 h after the simultaneous inoculation of Aspergillus niger Z₃⁴ and Trichoderma reesei,and the ratio of Aspergillus niger Z₃⁴,Trichoderma reesei,and Bacillus T_7.0 was 2 ∶ 1 ∶ 2. The optimal conditions of corn stalk pretreatment using Candida lipolytica was to preprocess 36 h with 2% inoculation scale and a 30- mesh sieve for stalk filtration.After this treatment,CMC enzyme activity reached 404.28 U / m L.