Abstract: In order to analyze the fatty acid composition and content of the aging process in different parts of Qinghai plateau yak meat, three sides of Qinghai plateau yak meat including supraspinatus, longissimus and semitendinosus were used to this test.Fatty acids profile of each depot were analyzed separately among the 0, 1, 2, 3, 5, 7 and 14 days by GC-MS in three parts.It was found that 22 kinds of fatty acids were detected in three parts of meat, eight kinds of saturated fatty acids, 5 kinds of mono-unsaturated fatty acids, 9 kinds of polyunsaturated fatty acids, respectively. And they were increasing at first and decreasing afterwards with ripening at slaughter. The fatty acid composition during ripening after three parts of the meat slaughtered were same but content were differences, n-6/n-3 ratio were between 1.0 ~ 3.0, they all had preferably fatty acid composition ratio.Through analysis the fatty acid composition and content in three different parts of Qinghai plateau yak with aging by the principal component analysis, it turned out that three sites 0 d, 1 d and 2 d had similarities, mainly containing two kinds of n-6 series and n-3 polyunsaturated fatty acids, for example linoleic acid ( C18: 2n6c) , arachidonic acid ( C20 : 4n6) , cis-8, 11, 14-eicosyl three acid ( C20: 3n6) , docosahexaenoic acid ( C22: 6n3) and monounsaturated fatty acid elaidic, and 3 d, 5 d and 7 d had similarities, most of this saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids increased during this time, but 14 d were different from the other times, mainly produced a large number of γ-linolenic acid ( C18: 3n6) .