Abstract: Changes in contents of 11 major physiochemical indexes and microbes in vinegar paste were detected continuously during fermentation process of Sichuan bran vinegar, analyzed the dynamic change rules of physiochemical indexes and microbes.Results indicated that there were close relationships between the changes in contents of physiochemical indexes and microbes; the changes in contents of physiochemical indexes were the results of the alternating action of microbes, mean while, which influenced microbial growth and enzyme activities during each period.According to the changes in contents of physiochemical indexes and microbes, the process of fermentation could be divided into four periods: days from 1st to 3rd were saccharification and alcohol fermentation; days from 3rd to 15th were alcohol fermentation and acetic fermentation; days from 15th to 22th were acetic fermentation; days from 22th to 30th were post maturation of vinegar, which interpreted that the fermentation process of Sichuan bran vinegar was a typical process of the concurrence of saccharification, yeast fermentation and acetic fermentation.It offered theoretical foundation and data reference to production of Sichuan bran vinegar.