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Based on two-step anaerobic fermentation process, this study compares the degradation feature of rice straw and the methane production potential of hydrolyzate under the conditions of dilute acid and dilute alkali pretreatment. In the HCl mass fraction range of 0.5%～2.5%（60℃）, the hydrolyzates in the tests of 1.0% and 1.5% obtained higher COD mass concentration. During dilute acid hydrolysis, the hemicellulose fraction decreased significantly, and the glucose concentration was low. In the NaOH mass fraction of 0.5%～4.0%, the hydrolysis of rice straw was weak in the tests of 0.5% and 1.0%, while the hydrolysis efficiency in the tests of 2.0% and 3.0% was high. When the mass fraction of NaOH was higher than 2.0%, cellulose, hemicellulose and lignin all decreased, and degradation rate of lignin was the highest. The tests of acid and alkali could achieve good hydrolysis efficiency at weight-in-volume ratio of 7.5%. Used the hydrolyzate from acid and alkali pretreatment for acid and alkali pretreatment for methane production, the average gas production of unit COD mass were 631～906mL/g from HCl hydrolyzate tests and 340～373mL/g from NaOH hydrolyzate tests in five feeding periods. The biogas production rate of unit mass was less affected by concentration of feeding, and mainly affected by different methods of hydrolysis of acid and alkali. The types of anaerobic fermentation were different in the acid and alkali tests, and the process of generating volatile acid was more sufficient in the tests of acid hydrolyzates.