Low- and full-fat cheeses were fermented by Lactobacillus acidophilus and adjunct cultures Streptococcus thermophilus. After ripening for 90d at 4°C, the main flavor substances were determined by gas chromatograph. The results showed that more than 28 main flavor components were founded in full-fat cheese, and at least 19 were founded in low-fat cheese. In low-fat cheese, there was a higher content of 9-(Z)- octadecenoic acid and 10-hydroxy-octanoic acid methyl ester, which their relative mass fraction were 19.20% and 18.79% respectively. In full-fat cheese, there was a higher content of hexadecanoic acid methyl ester and 9-Octadecenoic acid(Z)-methyl ester, which their relative mass fraction were 24.27%and 23.37% respectively.