The Wurinitu Mo deposit is one of the newly found molybdenum deposits in the southwestern part of the late Paleozoic–Mesozoic Erenhot–Dong-Ujimqin metallogenic belt(S-EDMB),Inner Mongolia,China. In the present study,the mineralization age of the Wurinitu deposit is constrained to 137.3 ± 1.3 to 131.9 ± 1.5 Ma based on a combination of the laser ablation–inductively coupled plasma–mass spectrometry(LA–ICP–MS) zircon U–Pb dating of the mineralization related fine-grained monzonitic granite and the post-mineralization granite porphyry. The results of zircon Lu–Hf isotopes,combined with the geochemical characteristics of the granites in the S-EDMB,suggest that the Wurinitu Mo deposit was formed in an extensional environment in relation to the subduction of the Paleo-Pacific plate in late Mesozoic. The Wurinitu deposit shares similarities with the classical Climaxtype porphyry molybdenum deposits in tectonic setting,mineral assemblages,and metal zonation. The Wurinitu Mo deposit is one of the newly found molybdenum deposits in the southwestern part of the late Paleozoic-Mesozoic Erenhot-Dong-Ujimqin metallogenic belt (S-EDMB), Inner Mongolia, China. In the present study, the mineralization age of the Wurinitu deposit is constrained to 137.3 ± 1.3 to 131.9 ± 1.5 Ma based on a combination of the laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U-Pb dating of the mineralization related fine-grained monzonitic granite and the post-mineralization granite porphyry. The results of zircon Lu-Hf isotopes, combined with the geochemical characteristics of the granites in the S-EDMB, suggest that the Wurinitu Mo deposit was formed in an extensional environment in relation to the subduction of the Paleo -Pacific plate in late Mesozoic. The Wurinitu deposit shares similarities with the classical Climaxtype porphyry molybdenum deposits in tectonic setting, mineral assemblages, and metal zonation.