The North Qingcaoshan granodiorite, located in the southern margin of Qiangtang block and the northern part of the Bangongco Suture zone, occurs as dykes or stocks in the carbonatite of Longge Formation(P2l). The study carried out zircon UPb geochronology and trace element geochemistry analysis of the granodiorite. The results show that the magmatic zircons have an weighted 206Pb/238U age of 1548±12Ma（MSWD=17）, belonging to the late Jurassic. This age is quite consistent with that of Rena Co adakite dacite. Petrochemical analyses indicate that the granodiorite belongs to quasialuminous and calcalkalic series, and is enriched in light rare earth elements and large ion lithophile elements, depleted in heavy earth elements and high fieldstrength elements, with weak Eu anomalies, indicating characteristic of typical islandarc magma. The insite trace elements analysis of zircons shows that the zircons are enriched in heavy rare earth and relatively depleted in light rare earth. All of the grains fall into the kimberlite range in the Nb/TaY discrimination diagram of source rock, and all the samples plotted in the discrimination diagrams of tectonic environments of granodiorite also imply that they were derived from mantle magma. The granodiorite formed by the partial melting of subducted oceanic curst after the BangongcoNujiang oceanic crust subducted northward to the certain depth in later Jurassic stage, with contamination of mantle wedge during magma uprising. During emplacement of the magma, part of magma formed intermediatefelsic granodiorite magmatic chamber while the other part erupted the surface to form the Rena Co decites.