The Beikengchang Molybdenite and multi-metal deposit in Zhangping city is located on the east part of the late Paleozoic depression of the southwestern Fujian province which has experienced the strong tectono-magmatic process with multi-phase mineralization since Mesozoic. The previous isotopic chronological data in the southwestern Fujian province indicated that there were mineralizations during early and middle Jurassic and early Cretaceous, but lack of the mineralization chronological record related to the late Jurassic magmatism. This paper selected molybdenite of the Beikengchang deposit of Zhangping City to study the Re-Os isotopic chronology. The Re-Os dating result combining with the country rock alteration and the relationship between deposit and intrusion indicates that the molybdenite minerlization experienced several phases, in which the small scale Mo minerlization occurred at 148.8±2.2Ma。The main Mo mineralization, characterized by the thin vein and net vein bearing inside sandstone of the lower Permian Cuipingshan Formation, was dated at the isochrono age about 139.8±2.3Ma~143.7±2.1Ma，representing late Jurassic and early Cretaceous minerlization event。And the mineralization material originated from late Jurassic granite magma in the southwestern Fujian formed after transformation from the Tethyan to Pacific domain.