The Duocaima Pb-Zn deposit, located on East Qiangtang Block in Qinghai Province, is a super⁃largePb-Zn deposit discovered in recent years. To strengthen the study of the metallogenic geological setting of the oredeposit, zircon U-Pb geochronology and petrogeochemical characteristics of granite porphyry were studied, and thepetrogenesis, magma source area, and tectonic setting were discussed. The zircon U-Pb age of granite porphyry wasdetermined to be 257.1 Ma ± 7.0 Ma, indicating its formation in the late Permian period. The granite porphyry exhibitshigh mass fractions of SiO2, Na2O, and K2O, with relative potassium enrichment, but depletion in Al2O3, Ca O, and MgO;it is enriched in light rare earth elements（LREEs）and large⁃ion lithophile elements（LILEs）such as Rb, Th and U,while relative depleted in heavy rare earth elements（HREEs）and high⁃field⁃strength elements（HFSEs）such as Nb,Ta, P and Ti. The chondrite⁃hormalized rare earth element（REE）diagram shows a right⁃leaning trend with moderateEu negative anomalies, indicating that the rock mass has undergone the fractional crystallization process of plagioclase,or some plagioclase remains in the source region. The granite porphyry falls within the metaluminous to weakly peralu⁃minous high⁃potassium calcium alkaline series, and exhibits characteristics of A2⁃type granite. The source region ismainly composed of metamorphic sedimentary rocks in the mid⁃upper crust, formed in an extensional setting related toslab retreat during oceanic crust subduction, and associated with the subduction of the Paleo⁃Tethys Ocean.