The study was aimed to research the effect of mixed strains optimized from sourdoughs on the quality of steamed bread with tartary buckwheat bran, through sensory quality, texture profile analysis and SPME-GC-MS analysis. The Angel Yeast and Hungary yeast considered as control groups. The results showed that: the order of sensory evaluation was mixed strains (82.2±2.3) > Hungary yeast (80.9±1.3) > Angel yeast (77.1±1.4); the hardness, chewiness, cohesiveness, gumminess and resilience of fermented steamed bread with mixed strains was the best one; on the springiness, the steamed bread fermented with Hungary yeast was the best one. In flavor compounds, Angel yeast, Hungary yeast and mixed strains were distinguish detected in 44, 49 and 52 flavors, respectively. the content of aldehydes, furans, esters, phenols which in mixed strains were higher than Angel yeast and Hungary yeast, and, there were three special esters detected in mixed strains, which means the mixed strains was more better for the formation of flavor in the buckwheat bran steamed bread. The mix strain is better for the fermentation of buckwheat bran steamed bread, which is more acceptable to consumers, and the strudy provided a theoretical support for mixed strains application.