Aiming to study the nutritional quality and volatile flavor composition of Xing'an lambs, taking Xing'an lambs as the object, the nutritional composition of mutton was analyzed by Kjeldahl method, Soxhlet extraction method and burning method, and the flavor substances of mutton were analyzed by solidphase microextraction combined with gas chromatography-mass spectrometry. The effects of different genders and different parts on the nutrition and flavor of lambs were compared. The results showed that the water content, crude fat content, crude protein content and ash content of Xing'an lambs were 75.32%, 2.41%, 19.81% and 1.11%, respectively. Totally 28 kinds of fatty acids and 18 kinds of amino acids were detected. The crude fat content in muscle of female lambs tended to be higher than that of male lambs. Quadriceps femoris muscle contained more unsaturated fatty acids and fat oxidation products. Totally 72 volatile flavor compounds were detected in Xing'an lambs, among which aldehydes and alcohols were the most important compounds. Different genders and different parts had certain influence on nutritional composition and flavor substance of lamb meat. The relative contents of seven volatile flavor compounds in female lambs were significantly higher than that in male lambs. Due to the low fat content, small odor and grease smell, the female lamb was more acceptable than the male lamb. The relative content of 2(5H)furanone and hexanol in longissimus dorsi muscle was significantly higher than that in quadriceps femoris, but the relative content of tridecaldehyde was significantly lower than that in quadriceps femoris.