Abstract: In this paper,rape straw is pretreated by three kinds of processes,pelleting,chopping and rubbing,for anaerobic digestion tests. In early 17 days,the pellets test acquire 90% of the potential cumulative biogas production,which is 2 d and 3 d ahead compared with the chopping and rubbing processes. The biogas yield of pelleting reaches 116.88 mL/g·VS,which is 31.50% and 17.97% higher than these of chopping and rubbing,respectively. Pelleting treatment may promovte the degradation of the hemicellulose during the anaerobic digestion. Pegradation ratio is approximately 20%. Based on the results,the net energy analysis are carried out,pelleting process obtains the highest net energy income,13.98% and 11.46% higher than that of chopping and rubbing,respectively.