In order to obtain the nutrition， the physical and chemical properties and sensory properties of Tan mutton， the longissimus protein， crude fat， moisture content， fatty acids， amino acids， free amino acid composition， thawing loss， the main flavor characteristics， color， volatile organic compounds， the main flavor and taste characteristics were analyzed， with the marketing Inner Mongolia mutton， Sunite and Chahar mutton as contrast. The results showed that， the highest protein and fatty acids content were found in Chahar mutton （P<0.05）， while the lowest protein content was found in the marketing samples， the lowest fatty acids content was found in the marketing and Sunit samples. The Sunit and Chahar mutton shared the richest crude fat and the lowest water proportion， as the lowest crude fat and the highest water proportion were found in the marketing samples. The marketing and Sunit mutton had the highest essential amino acids content （P<0.05）， and the ratio of essential amino acid to non-essential amino acid of Sunit mutton was the hightest （P<0.05）. The Cahar mutton with the lowest thawing loss （P<0.05）， while the Sunit mutton with the highest loss. The color characteristics of samples were improved after thawing， and the Tan mutton with a higher lightness， yellowness and reddness value. All samples had unique flavor characteristics and could be distinguished by the principal components of flavor substances for raw samples， while a similar flavor shared between the cooked marketing samples and Chahar mutton. Aldehydes were the main substances of mutton flavor， the volatile organic compounds of Tan mutton contained a higher content of methoxy - phenyl - oxime， and the cooked Tan samples had a strong bitter character. That was， a comprehensive analysis of nutritional attributes， physical and chemical properties and sensory characteristics could be carried out on mutton differentiation.