he Laojunshan ore district is an essential part of the W- Sn metallogenic belt in SE Yunnan Province, China. A series of large and super- large deposits such as the Dulong, Nanyangtian and Xinzhai Sn- W polymetallic deposits are distributed around the Laojunshan complex granite of Yanshanian. The Sn- W polymetals may have had multistage mineralization (e.g, Yanshan, Indosinian and Caledonian) because of complex geological history in the Laojunshan ore district. The Sn- W mineralization found in this ore district is mainly distributed in southern and eastern Laojunshan granite body, while northern deposits are relatively less studied. Especially in metallogenic chronology, most deposits still lack accurate isotopic chronology data, which limits the understanding of Sn- W polymetallic mineralization and in- depth geological exploration in this area. Changtian is a typical W (Sn) polymetallic deposit in northern Laojunshan granite. Caledonian and Yanshanian granites are distributed in the Changtian ore district.Due to the lack of chronology and geochemistry study, the understanding of W (Sn) mineralization is not based on actual geological and geochemical evidence. It is difficult to establish a reasonable metallogenic model, which restricts the in- depth geological exploration in the Changtian W (Sn) deposit. This study provides a high- precision Sm- Nd isotopic dating for scheelite and fluorite separated from the tungsten ore with two isochron ages of (97 Ma, scheelite) and (79 Ma, fluorite). These results showed that the Changtian W (Sn) deposit formed in the Yanshanian, and tungsten mineralization is closely related to the Laojunshan granite, but has little relation with the Nanwenhe granite. This study has enriched Sn- W mineralization of the Laojunshan granite of late Yanshanian and its scope of influence, as well as providing important geochronology data to further improve the geochronology framework of the Laojunshan ore district.