Abstract: The Liangshan molybdenum deposit was found in the western region of the Wugongshan-Qianshan subzone a few years ago. Based on an analysis of the mineralization features of the deposit, the authors determined LA-ICP-MS zircon U-Pb ages for the ore-bearing rocks in the Liangshan deposit. U-Pb dating of zircon by LA-ICP-MS reveals that the intrusion age of the Liang-shan porphyry granite is 168.2±2.3Ma. The ¹⁸⁷Re and ¹⁸⁷Os values of molybdenum from the molybdenum deposit were determined by the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Re-Os isochron of molybdenum suggests that the metallogenic epoch of the deposit is 168.9±1.4Ma, indicating that this deposit had a close relation with its host rocks, the magmatic activity had a close relationship with ore-bearing hydrothermal activities, and magmatic activity was an important factor for the formation of the Li-angshan molybdenum deposit. The metallogenic time of the Liangshan molybdenum deposit is consistent with south China first stage large-scale polymetallic mineralization of Yanshanian period (170Ma). The Liangshan molybdenum deposit was formed in the same regional metallogenic setting and resulted from regional tectonic magmatism, as a part of the South China Yanshanian mineralization.