Abstract: A dominant acetic acid bacteria (AAB) strain A3 was isolated and screened from Chinese traditional dough starter Jiaozi.According to the morphological,physiological,biochemical and 16S rRNA gene sequence characteristics,strain A-3 was identified as a strain of Acetobacter tropicalis.The acid production conditions of AAB strain A-3 were also optimized by single factor experiments.The results showed that the fermentation conditions were as follows:inoculum amount at 6%,pH 5.5,rotation rate with 180 to 200 r/min,ethanol content with 3%~5% (V/V) and temperature at 37℃.The acid production in the fermentation environment could reach 31.1 g/L.The results will not only lay foundation for the exploitation of AAB strains from dough starters,but also be helpful to improve the dough starters and explore the effects of microorganisms on dough fermentation characteristics.