The Jisong Pb-Zn deposit is one of the newly found deposits in the Tethys Himalaya belt. Orebodies mainly occur as veins in several nearly NE-striking faults. The veins are mainly composed of quartz, calcite, and sulfides. Hydrothermal sericite is genetically associated with zinc and lead mineralization and coexists with quartz, calcite, pyrite, sphalerite and galena. These sericite grains were separated for Ar-Ar isotopes dating. The results yielded a plateau age of (16.61±0.30) Ma at 760-860℃, with the corresponding isochron age being (16.64±0.30) Ma. These two ages are the same within the error, indicating that they can represent the formation age of the Jisong Pb-Zn deposit. Tethys Himalaya developed an Au (Ag) mineralization event in the main collisional orogenic setting, and the Ar-Ar age of the Jisong deposit indicates that Pb-Zn mineralization represented by Jisong in South Tibet occurred at late collisional stage. Combined with close spatial relationships as well as the similarities in time and Pb isotopes between the Jisong deposit and the Cuonadong leucogranite, the authors hold that the leucogranite possibly offered material and heat to the Jisong ore-forming hydrothermal system.