Abstract：At present, Re-Os isotopic dating of molybdenite is one of the direct ways to acquire the ore-forming age. Using TJA X-series ICP-MS, the authors dated five molybdenite samples collected from the Chilu molybdenum deposit and obtained model ages. The results show that the ore-forming age is about 105-106 Ma, quite close to the emplacement age of porphyritoid granite, adamellite and feldspar graphic granite (115±4 Ma, Rb-Sr isochron age), which are intimately related to the ore-forming processes in this area. This indicates that they are all products of late Yanshanian magmatism. The above outcome provides direct evidence not only for the research of late Yanshanian magmatism and mineralization in the Pucheng-Ningde NW-trending ore belt but also for the comparative study between the Pucheng-Ningde ore-forming belt and the Shanhang-Yuenxiao ore-forming belt, thus contributing to mineral exploration in these two belts.