Abstract: Bamboo is a kind of high biomass plants. It can be used as important raw material for bio-energy production. Pretreatment is the key technology for the production of cellulosic ethanol. Enzymatic hydrolysis experiments were conducted using the steam exploded pretreated Bambusa multiplex bamboo and Bambusa wenchouensis bamboo. The fermentable sugars were determined from the hydrolyzate and pretreatment filtrate solution by high performance liquid chromatography (HPLC). The results showed that the treatment of pre-soaked in 0.5% sulfuric acid could increase the total sugar yield by 49% compared with non-soaked; the strength of steam exploded pretreatment effected enzymatic conversion significantly, which reached the highest conversion rate of pretreated solids when strength index was 3.35, and the highest total sugars yield obtained when strength index was 3.65. 289.5 g fermentable monosaccharides were got from 1?000 g bamboo of dry basis. It is very important for accurately predicting the yield of sugars from steam exploded pretreated biomass through mass balance because the polysaccharide can be decomposed into the filtrate and the monosaccharide can be decomposed. The hydrolysis conversion of steam exploded treated bamboo is less than corn stover, for the bamboo has more lignin and more dense microstructure.