Abstract: The purpose of this experiment was to study the differences of volatile flavor substances and fatty acid composition in different parts of Small-Tailed Han Lambs, and to preliminarily evaluate the nutritional value of fatty acids in four parts. The contents of fat, protein, volatile flavor substances and fatty acid in hind leg, tenderloin, upper brain and lamb chop of 4-month-old Small-Tailed Han Lambs were analyzed. The results showed that the main flavor compounds of Small-Tailed Han Lambs were octanal, nonanal, octanol, 1-octene-3-ol, caprylic acid and decanoic acid. The types and relative contents of aldehydes, alcohols and esters in the tenderloin were high, which played an important role in the formation of mutton flavor. The ratio of unsaturated fatty acids to saturated fatty acids in upper brain was significantly higher than that in other parts, the ratio of polyunsaturated fatty acids to saturated fatty acids was more than 0.4, and the contents of monounsaturated fatty acids and polyunsaturated fatty acids were both high. Therefore, the composition of fatty acids in the upper brain is more consistent with the nutritional value of fatty acids.