Abstract: In this study, the authors identified the Eocene biotite monzonitic granite porphyry and quartz diorite porphyrite in the Xiariduo mining area, and obtained their crystallization ages of 41.6±0.3~41.7±0.3Ma and 41.1±0.2~41.2±0.2Ma respectively, thus determining the Eocene magmatic events in the Xiariduo mining area for the first time, with the Cu-Mo mineralization related to the structural-magmatic events. Rock geochemistry shows that biotite monzonitic granite porphyry and quartz diorite porphyrite have the same geochemical characteristics, with slightly higher SiO₂, rich K₂O and Na₂O, higher K₂O/Na₂O ratio and lower TFeO content, thus belonging to the weakly peraluminous and high potassium calc alkali-shoshonite series; in addition, they are relatively depleted in K, Ba, Nb, P, Ti and enriched in Th, U, Sr, Hf, thus having the characteristics of highly differentiated Ⅰ-typed granite with high Zr/Hf, Rb/Sr ratios and low Ti/Eu ratio. The formation of Xiariduo porphyry was related to the mixing of shell and mantle material, which was caused by the collision between Indian plate and Asian plate inducing a large-scale sliding system, which caused the sinking of the lower crust, the swelling of the soft-flow ring material, the partial melting of the enriched mantle, and the increasing accumulation of mantle magma.