The Lüshigou pluton is located in the Qiongheba ore concentration area in East Junggar. This pluton intruded into the host rock of the Lüshigou copper deposit. LA-ICP-MS U-Pb dating of zircons from this pluton yielded an early Carboniferous age of 354±1 Ma. The main rock type of the pluton is quartz-monzonite with many mafic-ultral mafic enclaves inside. These quartz-monzonites have high SiO₂ (62.31%~65.31%), Al₂O₃ (15.44%~16.29%), CaO (3.71%~4.89%) and K₂O (2.85%~3.54%) contents, exhibiting high-K calc-alkaline and metaluminous characteristics (A/CNK=0.93~0.99,A/NK=1.68~1.96), and belonging to I-type granite. The total REE values of them are low (90.82×10^-6~111.36×10^-6) with relative enrichment of LREE and Eu negative anomaly (δEu=0.68~0.87). The primitive mantle normalized trace element patterns are characterized by the enrichment of the LILE (K, Rb, Ba, Sr) and depletion of the HFSE (Nb, Ta, P, Ti). The quartz-monzonite has high Ba (758×10^-6~1 113×10^-6), Sr (401.8×10^-6~512.5×10^-6) values with high (La/Yb)_N, Sr/Y ratios, distinct Nb, Ta and Ti depletion, and are comprehensively called high Ba-Sr granitoid. These characters indicate that the Lüshigou pluton was probably formed by the magma-mixing of the mantle-derived mafic magma and crustal partial melting magma during the tectonic transition period from subduction to post-orogenic setting in the late Paleozoic.