Steam explosion is suitable pretreatment method for improving biogas production efficiency from rice straw. The initial production rates were increased by 59%, 166%, and 141% compared with that to the unpretreated rice straw. The methane gas was obtained after 60 days 535, 516 and 613 N ml/g VS that each has increased 114%, 104%, and 154% than to the rice straw unpretreated, respectively. Steam explosion pretreatment had a significant effect on remove lignin and hemicellulose and also opening up the crystalline structure of the cellulose of rice straw prior to anaerobic digestion. This demonstrates the ability of the steam explosion pretreatment to modify the structure of rice straw.