Three kinds of chemical pretreatment including 2% H2SO4, 2% NaOH, 1% H2O2+2% NaOH were used to pretreat water hyacinth and sugarcane bagasse biomasses. The pretreated biomasses were subjected to enzymatic hydrolysis. The relationship between the variation and the removal of the main components in pretreated biomasses and the effects of sugar production by enzymatic hydrolysis were investigated. Results showed that the yields of reducing sugar of water hyacinth pretreated by three chemical pretreatments had no obvious differences.The yields of sugarcane bagasse pretreated with 2% NaOH and 1% H2O2+2% NaOH were significantly higher than that pretreated with 2% H2SO4, and higher than those of water hyacinth under three kinds of pretreatment, indicating that it was superior to water hyacinth. Cellulose content, lignin and ash removal had a positive effect on yield of reducing sugar of samples pretreated. High yield of reducing sugar up to 81.54% was obtained by enzymatic hydrolysis of sugarcane bagasse pretreated with 1% H2O2+2% NaOH for 12 hours. 1% H2O2+2% NaOH is an effective pretreatment method for lignocellulose materials due to its relatively mildness and high efficiency of utilizing raw material.