Abstract: Using corn straw as raw material,corn straw was pretreated with the strains that can efficiently degrade lignocellulose after genome rearrangement breeding obtained in our laboratory,and the pretreated straw was fermented by anaerobic biogas. The optimum conditions for the treatment of straw by compound bacteria were determined by orthogonal test as follows:the initial pH value was 6.00,the content of corn straw was 2.0%,the inoculation amount of TR2-35 spore solution was 1.0%,and the inoculation amount of PR2-24spore solution was 0.5%;the optimal pretreatment time was determined to be 8 d through the regular detection of the fermentation broth of straw pretreatment. At this time,the p H value of the fermentation broth was 6.82,which is suitable for the growth of anaerobic methanogens. The COD content in the fermentation broth reached the maximum value of 10080 mg/L. The straw and its components also reached the peak of degradation,which is suitable for anaerobic biogas fermentation. Through the design of 1 L anaerobic biogas fermentation drainage gas gathering device,the effective reaction volume was 800 mL,and the biogas fermentation was carried out for20 d. The results show that the total gas production of the pretreatment group is 6083 mL,and the total methane production is 4316 mL,which are 61.14% and 93.63% higher than that of the non-pretreatment group respectively.