The acidic volcanic rocks are widespread in the Coqen basin, central Lhasa subterrane. Although numerous studies have been conducted on theses volcanic rocks, many uncertainties and controversies still remain as to their petrogenesis and geodynamic setting. In this paper, we take the volcanic rocks outcropped in both south and north sides of the Tanuochuo-Coqen fault as an example, and conducted an integrated study including zircon U-Pb dating and Hf isotopes, and whole-rock elemental geochemistry, aiming to obtain the precise ages, and to discuss magma source and geodynamic mechanism for their formation. Previously regional survey suggests that the volcanic rocks in the north side of the fault belong to the Lower Cretaceous Zenong Group and those in the southern side belong to the Paleocene Dianzhong Formation. However, our new zircon LA-ICP-MS U-Pb dating results demonstrate that volcanic rocks from both sides of the fault share similar ages of 110~120 Ma, indicating that they all belong to the Lower Cretaceous Zenong Group. Lithologically, volcanic rocks in the studied region are mainly a set of dacitic and rhyolitic rock association. They are chemically belong to high-K calc-alkaline series, and are enriched in LREEs and LILEs (e. g., Rb, Ba, etc.), depleted in HFSEs (e. g., Nb, Ta, Ti, etc.), showing typical signatures of arc-related igneous rocks under a subduction setting. All samples have enriched zircon Hf isotope compositions, with εHf(t) values of -12.9~-1.6 and tDM2 values of 1.28~1.99 Ga, indicating that these volcanic rocks were derived mainly from anatexis of the Paleoproterozoic to Mesoproterozoic basement of central Lhasa subterrane, with contributions of depleted mantle components. Based on a synthesis of geology, geochemistry and tectonics, we suggest that these volcanic rocks were likely generated under a continental marginal arc setting with a relatively thick crust, and the slab break-off of the southward subducted Bangong-Nujiang oceanic lithosphere occurred during the middle-late stage of Early Cretaceous is the most possible mechanism that triggered the magmatism in this area.