The Maliba molybdenum-copper-lead-zinc deposit is located in the southwest of the Sanjiang Tethys metallogenic belt and is hosted in the biotite adamellitic pluton, which belongs to the Xiaolonghe sequence of the Guyong pluton in the Tengchong granite belt. LA-ICP-MS zircon U-Pb dating of the biotite adamellite yielded the age of 78.6±1.2 Ma, corresponding to the Late Cretaceous and the Late Yanshannian. The Re-Os isotopic dating of molybdenite from the Maliba ore body yielded the isochron age of 78.5±3.7 Ma, slightly later than the diagenetic time, representing the first reported high precision ore-forming age in this area. Re-Os isotopes of molybdenite suggest that the major ore-forming material derived from crust. The Maliba molybdenum-copper-lead-zinc deposit has the ore-forming age similar to the intrusion age (~78 Ma), which is consistent with the Xiaolonghe intrusion age (79~65 Ma), indicating that the timing of hydrothermal activity was short and both ore-mineralization and intrusion-formation occurred in the early stage of magma activities. They were formed at the late stage of Yanshan and were produced during the gradually eastward subduction process of Neo-Tethys and by magmatic and hydrothermal activities caused by remelting of crustal.