A set of rhyolite strata, classified as middle-lower Jurassic series in geological mapping, are exposed in Siziwang Banner that across the border between North China Craton and Inner Mongolia-Daxinganling Orogenic Belt. Petrology, geochemistry, zircon U-Pb geochronology and Hf isotope analysis were performed to investigate the petrogenesis and geodynamic significance of the rhyolite strata. The weighted mean 206Pb/238U ages from the rhyolite and rhyolite porphyry by LA-ICP-MS zircon U-Pb dating are 262±2 Ma to 261±2 Ma, suggesting to the late Middle Permian. The volcanic rocks in Siziwang Banner belong to the high-K calc-alkaline series and shoshonite series, which are characterized by high silicon, alkali, and aluminum, depleted calcium and magnesium. The total amount of rare earth element values is high, and the chondrite normalized REE patterns are enriched in LREE relative to HREE, with moderate to strong negative Eu anomalies, enrichment of large ion lithophile elements Rb, Th and LREE, and depletion of Nb, Ta, Sr and Ba. The volcanic rocks have obviously negative Hf values (-25.97~-11.94), indicating that they may be derived from the partial melting of the ancient crust. The volcanic rocks have high-silica rhyolite characteristics, suggesting that they have undergone significant fractional crystallization and are related to the heating of deep mantle derived magma. The geochemical features and various tectonic discrimination diagrams of the volcanic rocks suggest that the volcanic rocks in Siziwang Banner area were formed in a post-collisional extensional setting.