The SuCha (Sumoqagan Obo) fluorite district, located on the northern margin of the North China continental massif, is the largest fluoriteonly district in the world. Fluorite mineralization occurs mainly within in Late Paleozoic volcano-sedimentary sequences of the Xilimiao Group. Previous studies show that the geological setting for the Su-Cha fluorite district is a late Paleozoic rift basin along the convergence zone of the Northern China continental massif and Siberian platform. The whole Xilimiao Group can be divided into 9 sections, with a total thickness of 5667 m. The No.4 and No.6 sections constitute the hanging wall and foot wall of the fluorite bodies located in the Su-Cha district, respectively. The two sections of the Xilimiao Gropup consist of mainly rhyolite (porphyritic rhyolite), rhyolitic tufflava, tuffaceous sediments, sandstone, marble, limestone, carbonaceous and argillaceous slates, with a certain amount of skarn lens. Locally, the volcano-sedimentary sequences of the Xilimiao Group have been intruded by a number of Mesozoic Yanshanian granitoid stocks. Both fresh rhyolite samples from the hanging wall and altered rhyolite samples from the foot wall of the fluorite bodies have been selected for the isotopic age dating. The SHRIMP U-Pb analytical data for the zircon grains both from the fresh and altered rhyolite samples are presented in this paper. The zircon grains separated from the fresh rhyolite sample give an average SHRIMP U-Pb age of 271±8 Ma, with MSWD value of 1.8. Meanwhile, the zircon grains separated from the altered rhyolite samples have yield an average SHRIMP U-Pb age of 276±10 Ma, with MSWD value of 1.9. Based on the zircon SHRIMP U-Pb age data mentioned above and combined with other geological evidences, it has been suggested that the rhyolite and its related fluorite deposit were formed within an Early Permian rift basin located along the collision zone of the Northern China continental massif and Siberian platform. The rhyolite is believed to be a product of late Hercynian tectonic-magmatic processes caused by coeval re-working of the deep-rooted faults occurring along the northern margin of the Northern China Massif. The rock-forming materials of the rhyolite sequences were derived from the mixed sources of mantle- and crustal-related components.