Abstract: In this study, the authors conducted detailed geochronological, geochemical and Hf isotopic researches on the volcanic rocks of the Manketouebo Formation from the Suolun area in the central Da Hinggan Mountains. LA-ICP-MS zircon U-Pb dating reveals that the Manketouebo volcanic rocks from the Suolun area were formed in 140~138Ma, i.e., the early Early Cretaceous rather than Late Jurassic as previously thought. Geochemical data show that the volcanic rocks are characterized by high silicon, rich alkali, weakly peraluminous nature (A/CNK=0.99~1.34) and high degree of differentiation, thus belonging to high-k calc-alkaline series. They are enriched in LILEs (Rb, Th, U, K) and LREEs, and depleted in HFSEs (Nb, Ta, Ti, P). Their zircon Hf isotopic compositions show that the Manketouebo volcanic rocks of the study area have relatively high ε_Hf (t) values (+4.06~+8.24) with the two-stage model ages ranging from 936Ma to 664Ma, implying that they were probably derived from partial melting of juvenile crustal materials that accreted from the depleted mantle. According to the regional geologic data, it is concluded that the volcanic rocks of the Manketouebo Formation formed in a post-orogenic extensional setting, which was probably closely related to the collapse of orogenic belt after the closure of Mongol-Okhotsk Ocean.