The Greater Khingan Mountain, located in the eastern part of the Central Asian orogenic belt, is composed of Erguna block, Xing’an block, Songnen block, and their suture zones. However, the timing, locations, and evolutionary processes of the amalgamation of these blocks have been key scientific issues of controversy within the geological community. In this paper, the Late Carboniferous medium fine grained monzonitic and medium fine grained granodiorite in the Huma area, northern Greater Hinggan Mountains are studied, conduct LA-ICP-MS zircon U-Pb geochronology and whole-rock elemental composition studies, investigate rock genesis and magma source regions, analyze the tectonic setting of petrogenesis, and attempt to constrain the timing of the closure of the ancient Paleo-Asian Ocean. The research results shows that the age of the medium fine grained monzonitic and medium fine grained granodiorite are (310.3±2.6)Ma and (313.4±2.5)Ma, respectively. Both types of rock formations share characteristics of high silicon, high aluminum, high alkali, low calcium, low magnesium, and weakly peraluminous. They belong to high potassium calc alkaline series rocks, rich in Rb, K, Th, U and other elements, and depleted in Nb, Ta, P, Ti. The content of P2O5 and Al2O3 decreases with the increase of SiO2, and the content of Th and Y increases with the increase of Rb, showing the characteristics of I-type granite. In conjunction with the regional magmatic zircon Hf isotope composition features, it indicates that the magma originated from the partial melting of basic rocks of amphibolite facies in the late Neoproterozoic-Phanerozoic neoaccretionary crust, and experienced a certain degree of fractional crystallization. Integrating geochronology, geochemistry characteristics and regional tectonic evolution, it is suggested that the Late Carboniferous granites in the northern Greater Khingan Mountains were formed in the post-collision environment after the collision of the Xing’an block and the Songnen block.
