Abstract: Brettanomyces bruxellensis plays a pivotal role in the solid-state fermentation process of Sichuan Shai vinegar, primarily due to its capacity to generate unique flavor compounds. This study aimed to delve into the mechanisms by which B. bruxellensis contributed to the fermentation of Sichuan Shai vinegar. The mother liquor of Sichuan Shai vinegar was selected as the research sample and successfully isolated and screened a strain, designated Y7. The strain was identified as B. bruxellensis through a comprehensive identification process involving morphological observation, physiological and biochemical tests, and internal transcribed spacer identification. Further analysis was conducted on the growth characteristics, enzyme production capabilities and fermentation attributes. The research revealed that the optimal growth conditions for Y7 were 32 hours, 28 ℃, pH4.5, and a 4% ethanol concentration. After 48 hours of cultivation at 28 ℃, the specific activities of esterase, β-glucosidase, amylase, and acidic protease reached 6.84±0.117, 9.52±0.194, 67.75±1.461, and 5.13±0.023 U/mL, respectively. Following a 5-day static fermentation in a rice-based medium, the alcohol content was 1.63%vol±0.152%vol, the total ester content was 1.457±0.095 g/L, and the reducing sugar consumption rate was 50.18%. A total of 15 volatile flavor compounds produced by Brettanomyces bruxellensis during single-strain fermentation were detected using HS-SPME-GC-MS technology, including three alcohols, three aldehydes, two acids, five esters, and two phenols. Moreover, the study found a significant correlation between B. bruxellensis and characteristic flavor compounds of Sichuan Shai vinegar, such as acetaldehyde, 4-ethyl-2-methoxyphenol, and benzaldehyde. These findings provide a scientific basis for understanding the role of B. bruxellensis in the formation of the unique flavor profile of Sichuan Shai vinegar.