Based on a systematic collection of geological data from the eastern Hexi Corridor, this study conducted petrological and elemental geochemical research on the region and discussed its tectonic background. The granites in the Moon Mountain area of the Hexi Corridor are generally high in silica (SiO2 content ranging from 73.61% to 78.14%, with an average of 76.53%) and aluminum (Al2O3 content ranging from 8.76% to 12.98%, with an average of 10.41%). The total alkali content is moderate (K + Na content ranges from 6.38% to 6.88%), with a K₂O/Na₂O ratio of 0.54 to 0.59, indicating a high sodium component. The A/CNK ratio ranges from 0.68 to 0.94 (<1.1), suggesting that the samples are transitional between over-alkaline and sub-alkaline, and belong to I-type granites. The Zr + Nb + Ce + Y content ranges from (151.56 × 10⁻⁶ to 156.56 × 10⁻⁶), with an average of 153.89 × 10⁻⁶. Rock formation environment discrimination diagrams show that the samples all fall within the range of volcanic arc granites, indicating that they formed in a volcanic island arc setting and exhibit characteristics of arc granites.