Located in Dong Ujimqin Banner of Inner Mongolia, the Highland 1017 Ag polymetallic deposit tectonically belongs to the easternmost part of Early Paleozoic Chaganobo-Aououte-Chaobuleng tectono-magmatic belt on the southeastern margin of the Siberian plate. The ore bodies mainly occur in sandstone of the Upper Devonian Angeeryinwula Formation and adamellite of middle Hercynian period, and the commercial types of ores include quartz-vein type and altered adamellite type. Fluid inclusions are well developed in quartz-type ores, and the majority of fluid inclusions consist of two phases of vapor and liquid. The homogenization temperature and salinity are in the range of 175～225℃ and 4.42%～11.46%, respectively. The ores have uniform sulfur isotopic composition with δ³⁴S varying from 3.4‰ to 8.0‰, suggesting that sulfur originated from the mixing and equilibrium processes of sedimentary and magmatic sulfur. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of sulfides from the ores vary in the range of 18.274 0～18.399 6, 15.539 9～15.561 6 and 38.036 3～38.177 2 respectively, implying that the lead was derived mainly from the interaction between uranium-depleted upper mantle and lower crust, and that ore-forming fluid was also contaminated by radioactive uranium-rich upper crust during its upward migration. δD_V-SMOW values vary from -103‰ to -125‰ and δ¹⁸O_V-SMOW range from 6.9‰ to 13.9‰, indicating that ore-forming fluid was the mixture of magmatic water and meteoric water. In combination with the regional metallogenic geological setting and geochemical characteristics of the Highland 1017 Ag polymetallic deposit, it is inferred that the ore-forming material was derived from the mixing process of deep magma and the upper crust, and the ore-forming fluid was the mixture of magmatic water and meteoric water. This deposit can be genetically regarded as the granitoid magmatic hydrothermal deposit with middle-low temperature and salinity.