Abstract: Four aroma-producing yeast strains were screened from 'qu' of Baoning vinegar. The fungir DNAITS area was amplifed and the diagram of phylogenetic tree was constructed,which determined the four strains Y7 and Y9, Y10, Y18 were Wickerhamyces anomalus and Candida melibiosica, and the GC- MS technology was used to detect the species and relative content of volatile flavor in fermentation substances.The results showed that the flavor substances of Y7,Y9,Y10,Y18 were number of 26,30,21,22,among them.The Y9,Y10,Y18 had more alcohols sort in species,and the higher relative content of alcohols sort was ethanol and benzene ethanol. The Y7 had more ester substances in species,among the ester substances,the relative content of ethyl acetate was up to 25.238%,which full of rich aroma. The species and relative content of aroma-producing yeast was difference,which gave different types of aroma to the vinegar,and had great significance for the flavored vinegar