Abstract:The Danchi metallogenic belt in northwestern Guangxi is an important non-ferrous metal mining base in south China. He, Ar isotopes of fluid inclusion trapped in pyrite from Ma"anshan Pb-Zn deposit and Dashan Sn-Zn deposit of Mangchang ore field, Tongkeng Sn-polymetallic deposit of Dachang ore field and Qianzhupo Pb-Zn polymetallic deposit of Wuxu ore field have been studied in this paper. The results indicate that 3He/4He values (0.79～5.32Ra) of the ore-forming fluid are between those of crustal fluid (0.01～0.05Ra) and mantle fluid (6～9Ra)；40Ar/36Ar values (273～349) are close to or slightly higher than the atmospheric eigenvalue (295.S5). He and Ar isotopes show that mantle fluid was involved in the mineralization in the area, and the ore-forming fluid was a mixture of mantle fluid, crust-sourced magmatic fluid and saturated atmospheric water. Based on the comprehensive study of Devonian exhalative deposition, granitic intrusion and tectonic characteristics, it is concluded that mantle fluid involved in mineralization is a regional event in the area. Mantle fluid is mainly derived from mantle components rising along NW deep faults during the crust-mantle interaction. The diagenesis and mineralization of Danchi metallogenic belt are the products of the same tectonic-thermal event in the Late Yanshanian period, and belong to epigenetic hydrothermal filling-metasomatic mineralization.