In this study, we carried out a comprehensive research including petrochemistry, zircon U Pb dating and Hf isotopic composition analysis on the rhyolite in the Zhaxikang deposit, Lhünzê County, South Xizang(Tibet). Chemical analyses show the rhyolite has high SiO2(SiO2=73.37%~77.08%), low alkaline (Na2O+K2O=3.48%~3.56%), low Mg and Ca (MgO=0.36%~0.49%,CaO=0.50%~0.66%), strong peraluminous (A/CNK=2.16~2.62), enriched in LILEs such as Rb, Th, U, Pb and HFSEs such as Hf and Nb, and depleted in Sr and Ti. The rocks also display high total REE contents (∑REE=295.71×10-6~343.82×10-6), enrich LREE and differentiate obviously (LREE/HREE=10.00~12.62), with weakly negative Eu anomalies (δEu=0.57~0.88), without cerium anomalies. LA MC ICP MS zircon U Pb chronology indicated that the Zhaxikang rhyolite emplaced at 135.33±0.62Ma. Zircon Hf isotope analyses show relatively homogeneous Hf isotopic compositions with εHf(t) values from -9.5 to -24.2, which indicate that the rhyolite are likely generated from crust. The rhyolite is the product of the Early Cretaceous magmatic activity and may be the part of Comei—Bunbury large igneous province.