Minqin lamb, Dongxiang tribute lamb, and Subei Snow Mountain lamb are geographical indication lamb products from Gansu Province; due to the influence of environmental factors such as regional climate, forage availability, and water resources, these lamb products exhibit potential variations in eating quality and nutritional composition. To investigate the characteristic quality differences among Minqin lamb, Dongxiang tribute lamb, and Subei Snow Mountain lamb, this study utilized frozen hind leg meat samples from three breeds of sheep raised in confined housing (aged 6-8 months) as experimental materials. After thawing, the quality differences among the three lamb varieties were compared and analyzed, and a comprehensive evaluation was conducted using Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). The results showed that the pH values of the three lamb varieties ranged from 5.76 to 5.82, with no significant differences observed between them (P> 0.05); Minqin lamb exhibited higher L* and a* values, the lowest shear force (3.82 kgf), and the lowest cooking loss (P <0.05), indicating tender meat texture and excellent water-holding capacity; the Na, Mg, P, K, and Fe concentrations in Minqin lamb were significantly higher (P <0.05), whereas the Ca and Zn concentrations in Dongxiang tribute lamb were the highest; a total of 16 amino acids were identified; Minqin lamb showed dominant levels of TAA, EAA, FAA, and NEAA (P <0.05), with an EAA/TAA ratio of 41.52% and an EAA/NEAA ratio of 71.54%; Subei Snow Mountain lamb exhibited significantly higher total fatty acid and monounsaturated fatty acid concentrations (P <0.05). OPLS-DA identified 13 characteristic differential indicators (VIP> 0.8), which may be closely associated with regional environmental factors. This study reveals the variations in lamb hind leg meat quality across different regions of Gansu Province and provides a theoretical reference for the development of the livestock industry in Gansu.