Abstract: This paper has reported the field geology, petrography, major and trace elements, zircon U-Pb age and Lu-Hf isotopic data for the granite from Yimianpo area, Zhangguangcai Mountain. The granite is high in SiO2 and Al2O3. A/CNK=1.04~1.07, (K2O+Na2O)=8.24%~8.85%，and K2O/Na2O=1.58~1.68, belonging to peraluminous and I-type high-K calc-alkaline series. The granite is enriched in LREE, Rb, Th, U, K and depleted in Nb, Ta, P, Ti with significant negative Eu anomalies. It has 206Pb/238U weighted mean age of 211Ma±4Ma (MSWD=1.4, 2σ), which represents the crystallization age of the granite. Zircon Hf isotope composition is εHf(t)=+1.75～+13.81, TDM2=367~1136Ma. Therefore, the I-type granite in the study area might have been formed in a typical post-collsional tectonic setting and resulted from partial melting of juvenile basaltic lower crust in an extensional setting.