Abstract: Lespedeza stalks were subjected to steam pretreatment at 210℃ for some residence time before simultaneous sacchari-fication and fermentation (SSF).Cellulose-derived glucose was extensively utilized by yeast during SSF.The ethanol yield after steam pretreatment of the lespedeza stalks at 210℃ was 59.3 %, 72.8 % and 62.2 % of theoretical yield when the residence time was 2, 4 and 6 min, respectively, whereas the highest yields fromα-cellulose were 92.7 % of theoretical yield.Steam explosion pretreatment of lespedeza stalks increased the ethanol yields by a factor 4.4, from 16.4% (untreated) to 72.8 % (steam explosion pretreated).