Abstract: To clarify the quality characteristics of sheep breeds in different regions of Xinjiang, Taking Kazakh sheep from Northern and Lop sheep from Southern Xinjiang, After slaughter, the longest muscles of the back were selected and their edible quality, basic nutrients, minerals, amino acid composition and metabolites were analyzed. The results showed that both types of lamb pH were 5.56~5.89, the color difference was not significant (P>0.05), but the Kazakh lamb color was more bright red. The shear and cooking losses of Lop sheep were significantly lower than that of Kazakh sheep (P<0.05), the calcium and sodium content were higher in Kazakh sheep, and the magnesium, selenium and zinc content of Lop sheep were more abundant (P<0.05). Two varieties of lamb had similar nutrients. The crude protein content of Lop sheep was significantly higher than that of Kazakh sheep. Its amino acid composition conforms to FAO/WHO high quality protein standard. The histidine content was significantly higher than that of Kazakh sheep (P<0.05). A total of 67 amino acid metabolites, including goose muscle peptides, levotrophin and glutamine, were detected in lamb samples 24 hours after slaughter. OPLS-DA and mono-variable analysis screened 16 markedly different metabolites, with significant upregulation of 11 metabolites including arginine, glycine and proline in Lop's sheep metabolites (P<0.05) involving arginine biosynthesis and its associated metabolic pathways. Alanglycine, taurine and ethanolamine showed very high species identification performance, with an area up to 1.00 under the ROC curve. This study provides new insights into the relationship between amino acid metabolism and meat properties, and provides important reference for the management and quality improvement of meat sheep in Xinjiang.