Abstract: Response surface methodology (RSM) was adopted to study the key parameters in order to increase the yield of xylose in saccharification of rice straw by dilute sulfuric acid hydrolysis. A second order quadratic equation was established, and the applicability of the model and interaction involved factors on predicting the yield of xylose was verified. The results indicated that the effects order of three factors on the yields of xylose were as follows: acid concentration, temperature and time. The optimal levels for achieving the highest yield of xylose were obtained, including dilute sulfuric acid concentration of 1.53%, temperature of 121℃ and reaction time of 56 min. The yield of xylose reached 78.12% under optimized conditions. Hydrolysis runs were conducted under the optimum condition and the results showed the models fitted well the experimental data and the model was feasible.