In order to improve the hydrolysis efficiency of cellulose materials, an artificial composite system CN6 was constructed by using different substrates and complementary enzymes. By detecting the filter paper enzyme activity and cellulose degradation rate, the optimum fermentation conditions of CN6 were determined as follows：culture temperature of 30～37℃ and initial pH value of 7.0. The metabolic process of CN6 was proved to be stable. The complex strains CN6 was applied to biogas fermentation of cow dung as raw material in a laboratory scale reactors. The results showed that the volatile fatty acid (VFA) was increased by 26.5%～30.6% in 0～15d of fermentation. At the end of fermentation, the cellulose degradation rate and cumulative biogas production were increased by 6.8% and 18.4% compared with that of the control.