Abstract: Volatile components of traditional fermented yak yogurt in the western Sichuan plateau were detected by headspace solid phase microextraction gas chromatography- mass spectroscopy( HS- SPME / GC- MS),and common yogurt products available from supermarkets were used as controls. The results showed that the main flavor components of traditional fermented yak yogurt in the western Sichuan plateau consisted of ethanol( 13% ~34%),3- methyl-1- butanol( 4% ~15%),2- methyl-1- butanol( 1% ~8%) and ethyl acetate( 1% ~10%),which were obviously different from common yogurt products. Abundant alcohols provided yak yogurt with alcohol aroma.Compared to common yogurt products,the acetaldehyde,2,3- butanedione and 3- hydroxy-2- butaone accounted for smaller proportions in the traditional fermented yak yogurt,and the total percentage of short and medium chain fatty acids( C₂~ C₁₀₎ in yak yogurt was lower. Generally,thevolatile components of the traditional fermented yak yogurt were complex and dispersive,and the flavor of yak yogurt was mixed with milk aroma and alcohol aroma.