Abstract: The effects of different concentrations of NaOH pretreatment on anaerobic digestion of rice straw for biogas production were investigated. The tests were carried out in self-made anaerobic digestion equipment with rice straw as raw material. The results showed that the components of rice straw were damaged after NaOH pretreatment, and the component of hemicellulose was obviously degraded. Gas yield of pretreatment groups increased significantly compared with the control group. In addition, the fermentation time was shortened. The pretreatment group with NaOH concentration of 6% had the largest gas production yield which was 246.6 mL/g dry material, and the methane content was up to 50%. On the whole, the best concentration of NaOH pretreatment for rice straw was 6%.