Corn stover was pretreated using different soaking conditions at mild temperature. Among the tested conditions, the best was 1% NaOH+8% NH4OH，50°C，48 h, Solid-to-liquid ratio 1:10. The results showed that soaking pretreatment achieved 63.6% deligniﬁcation, retained the xylan and glucan. After enzymatic hydrolysis, conversion rates of xylan and glucan were 70.9% and 78.5%, respectively. The pretreated filtration re-soaking cause 52.7% xylan and 65.0% glucan conversion. NaOH+NH4OH treatment can be performed under mild conditions, gives a good buffering effect, low carbohydates degradation and extensive removal of lignin. Additionally, simultaneous sacchariﬁcation and fermentation was conducted with pretreated corn stover to assess the ethanol production. For the whole process, 0.15g ethanol /g corn stover was achieved using Saccharomyces cerevisiae Y5, and 0.19g ethanol /g corn stover when using Pichia stipitis.