Abstract: Bacillus, one of the dominant microbial genera in Baijiu brewing, is recognized as crucial to the fermentation process, with the flavor and quality of Baijiu being directly or indirectly impacted through its metabolic functions. The species diversity, enzymatic activities, and flavor-enhancing capabilities of Bacillus in the Baijiu brewing environment are systematically investigated. This analysis is conducted to emphasize the critical role played by Bacillus in alcohol production, particularly through its synthesis of hexanoic acid and ethyl caproate, and to optimize its industrial potential via strain selection and metabolic pathway modulation. Furthermore, the broad potential of Bacillus in Baijiu brewing is also explored. Bacillus application has significant potential in enhancing Daqu, Fuqu, fermented grains, and other important linkages. This work offers strong theoretical support and useful insights on the microorganisms involved in Baijiu brewing, particularly Bacillus.