[Objective] The research aimed to explore the efficiency of ethanol production under the optimal conditions of separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF).[Method] Under the optimal conditions of hydrolysis and fermentation,SHF and SSF process were designed respectively.SHF process was conducted under the optimal conditions of hydrolysis and fermentation separately,while SSF process was carried out at the optimum temperature of hydrolysis and fermentation.[Result] In SHF process,the efficiency of ethanol production was similar during both supernatant and mixture fermentation,and yeast was more active during the mixture fermentation.In SSF process,the efficiency of ethanol production was higher at 35 ℃,and the production of xylose was higher than that in hydrolysis process.[Conclusion] Under the experimental conditions,the efficiency of ethanol production during simultaneous saccharification and fermentation was higher than that during separate hydrolysis and fermentation. [Objective] The research aimed to explore the efficiency of ethanol production under the optimal conditions of separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). [Method] Under the optimal conditions of hydrolysis and fermentation, SHF and SSF process were designed under the optimal conditions of hydrolysis and fermentation separately, while SSF process was carried out at optimum temperature of hydrolysis and fermentation. [Result] In SHF process, the efficiency of ethanol production was similar during both supernatant and mixture fermentation, and yeast was more active during the mixture fermentation. SSF process, the efficiency of ethanol production was higher at 35 ° C, and the production of xylose was higher than that in hydrolysis process. [Conclusion] Under the experimental conditions, the efficiency of ethanol production during simultaneous saccharification and fermentation was higher than that du ring separate hydrolysis and fermentation.