Abstract: The Dengfuxian W-Nb-Ta deposit is one of the important W-Sn multi-metal ore deposits in Xitian area of Hu'nan Province. ⁴⁰Ar/³⁹Ar dating of muscovite for the sample collected from the top of granite-aplites in Jinzhulong Nb-Ta zone yielded a ⁴⁰Ar/³⁹Ar plateau age of 148.3±1.1Ma, suggesting that the ore-forming process occurred in Late Jurassic. Combined with the existing chronological data of the Xitian area, the authors hold that the W-Sn multi-metal ore deposits of the Xitian area including the Dengfuxian W-Nb-Ta deposit had the same geodynamic condition, and were formed by the extension and thinning of the Mesozoic lithosphere in South China.