Abstract: A high acid producing acetic acid bacteria( Q2534) was screened from traditional steamed bread fermentation agent in the south of Shanxi.The identification and acid production optimization have been done to it.It has been identified as Acetobacter tropicalis based on 16 S r DNA method. On the basis of single factor experiments,the best fermentation conditions and medium composition were optimized by response surface analysis method.The best fermentation conditions were as follows: temperature 32 ℃,rotation rate 140 r·min~(-1),p H6.0 and alcohol content 3.4%( v / v). Under these conditions,the yield of acetic acid of this bacteria can reach26.74 g / L.The results have some effects on exploitation and application of the resource of acetic acid bacteria that got from traditional fermenting agent of Chinese steamed bread.