The acid and alkali pretreatment method was employed to explore the different effect of straw pretreatment on reducing sugar component and methanogenic features of straw hydrolysate. The results indicated that xylose was the major component in the mixed reducing sugar solution in the tests with higher HCl concentration(9% and 7%), however that of glucose was slightly higher than xylose in the tests with lower Ca(OH)2 concentration(2 g/L and 4 g/L) in the early 48 h. Methanogenic features with different ratio of glucose and xylose was studied and indicated it was significantly affected by the mole fraction of glucose in mixture. The biogas yield increased with the xylose increasing, and the lowest biogas 191.75 mL/g was in the test of 100% glucose，while the highest biogas yield 633.14 mL/g and energy conversion efficiency 26.40% were both in the test of 25% glucose. There was certain biogas production delay for pure xylose test.