Abstract: The Longwangpai molybdenum-polymetallic deposit field in the East Hunan province is a new metallogenic region with great potential of mineral prospecion discovered through a international project. Authors collected the molybdenites from the drilling holes in the fracture zone-alterated rock type molybdenum-polymetallic deposit in exocontact zone of the Longwangpai granite rock-body. Its isochron age is (146.3±1.8) Ma， which suggests that its mineralization is related to the Early Yanshanian granite intrusive activities.