Abstract: In this thesis, cottonseed husk as raw material, the basic effect of alkaline pretreatment of H₂O₂ preconditioning factors and after pretreatment of enzymatic hydrolysis conditions for optimum were studied. Alkaline concentration of H₂O₂ 2.5%, 30℃ processing time 12～14h, under this condition 31.7% cottonseed husk xylan content was obtained. At last, the optimum enzymolysis conditions were established:the ratio of solid to liquid 1∶15 concentration, enzyme amount 3%, 50℃ for 24h, cottonseed husk xylan extraction rate and the rate of hydrolysis were 18.3% and 57.8%.