In this paper,alkali pretreatment of corn,wheat and rice three stalks,as well as succinc acid(SA) production by simultaneous saccharification and fermentation(SSF) from the pretreated stalks were investigated.Results showed that when corn,wheat and rice stalks were pretreated with 1.0% NaOH concentration at 120℃ for 2 h,the rates of both lignin removal and cellulose-hemicellulose remains were more than 85%.In the conditions of cellulose and cellobiase added,30.74 g/L,24.98 g/L and 26.57 g/L SA were achieved using the corn,wheat and rice pretreated stalks as stuff respectively,when SSF were performed 72 h by Actinobacillus sucinogenes F3-21 in 150 mL flask.While in a 7 L stirred bioreactor,SA concentration were obtained 40.21 g/L,30.06 g/L and 39.07 g/L in 72 h,and its yields of each per gram of pretreated stalks reached 0.50 g,0.38 g and 0.49 g correspondingly.Moreover the extraction of SA by precipitation from the broth of corn stalk SSF was attempted.SA crystal with a purity of 99.89% was obtained.The results suggest the feasibility of SA production by SSF from corn,wheat and rice stalks.