Three N-S-trending granite belts were developed within the Yidun arc magmatic zone, which is sandwiched between Garze-Litang and Jinsha River composite tectonic zones. The middle belt, i.e. the Yuershan-Genie granite belt, is composed of more than 20 granite intrusions and related Ag, Zn, Pb-Zn deposits. Our study shows that the batholith of Genie granite can be classified into granodiorite, adamellite and potassium-feldspar granite, with the adamellite dominant in this area. Zircon LA-ICP-MS U-Pb dating for the adamellite yields a weighted mean age of 89.9±3.6 Ma. Geochemical analysis shows that the Genie granite is characterized with high contents of Si, Al, K and low Na, indicating a typical to S-type granite. ASI>1 and CaO/Na2O ratio of about 0.1 indicate that the magma was sourced from continental crust and likely mudstone. The Genie granite has a total REE amount of 228.83×10-6. REE distribution curve of Genie granite is near flat, and this is in accordance with that of remelted continental crust granite. Weak fractionation of LREE and HREE and strong negative Eu anomaly (δEu=0.13) demonstrates strong crystallization differentiation. Sr depletion, U enrichment and average Rb/Sr value (14.97) indicates that the magma of Genie granite was derived from upper continental crust. Diagrams of Rb vs (Y+Nb), (Rb/30)-Hf-(Ta×3), and R1 vs R2 also suggest that the Genie granite was formed in a post-orogenic and extensional tectonic setting, following closing of the Garze-Litang and the Jinsha River oceanic basins.