Located in the northwest part of the Erlian—Hegenshan fault belt, Baiyintuga area has wide distribution of Late Paleozoic granite, comprising mainly byporphyriticmonzogranite andalkali granite, which is a part of the accretion zone on the Late Paleozoic continental margin of southeast Siberian plate. Zircon LAICPMS UPb datingage of monzogranite and alkali granite, and petrogeochemical testing were conducted, gained ages 3028±13Ma（MSWD=14）and 3011±06Ma（MSWD=084）of the graniterespectively, belonging toLate Carboniferous.Petrogeochemicalresearches indicate that the granites belong to Potassium basaltic seriesand is characterized by high in silicon (SiO2=7083%～7083%)，alkali (Na2O+K2O=1158%～132%), low calcium (CaO=050%～122%) and magnesium (MgO =011%～033%). The granite is metaluminous to weak peraluminous with A/CNK=081～101.The granite rockare enriched in Rb, Th, U (large ion lithophile elements (LILEs)), but depleted in Ba, Sr and high field strength elements (HFSEs) Nb, Ta, P, Ti; LREE is enriched and HREE relativelydepleted，with obvious negative Eu anomaly (δEu=011～043).The initial magma temperature (75933～80181℃) and Petrogeochemical analysis showed that the Baiyintuga granite has the characteristics of Atype granite. The low Nb/Ta(738～1950),Zr/Hf (2961～3526) and Sm/Nd (022～032)values indicatedthat its source rock iscontinental crust. Comprehensive studies have shown thatthe Baiyintuga granite were from partial melting of continental crust greywacke and formed in extensional tectonic system of the postcollisional Siberian plate and north China plate inLate Carboniferous,which provided new constraints and a supporting instance on the tectonic—magmatic evolution of the Great Hinggan(Da Hinggan)—Inner Mongolia Orogenic Belt in Late Carboniferous and on close time of the PaleoAsian Ocean.