The Shuangpengxi gold deposit, as one of the most important gold deposits in northwest China, is located in the Tongren ore concentration area of Qinghai Province. Gold mineralization occurs within skarn that lies between granodiorite and marble. The ore bodies are in lenticular and veinlike forms. Ores are mainly composed of chalcopyrite, pyrrhotine and pyrite. Gangue minerals comprise diopside, garnet, calcite and sericite. The main types of rock alterations are skarnization, silicification, carbonatization, brecciation and ferritization. The tectonic setting, material source and genesis of the ore deposit are discussed on the basis of trace elements, REE, fluid inclusions and isotope geochemistry of ores and wall rocks as well as characteristics of the ore deposit. Studies show that ores and granodiorite have similar chondrite-normalized REE patterns and are enriched in light REE with a moderate Eu negative anomaly but no Ce anomaly. Microthermometric homogenization measurements of the fluid inclusions show that temperatures are from 215℃ to 468℃, corresponding salinities vary from 1.40％ to 13.40％ NaCleq, and densities vary from 0.55 g/cm³ to 0.85 g/cm³. The metallogenic pressure is 2.25 MPa～20.61 MPa. and the ore- forming fluids belong to NaCl-KCl-CaCl₂-H₂O types, especially enriched in CO₂,CH₄ and C₂H₂. Sulfur isotopic compositions of sulfides from ores show that the values of δ³⁴S from the early depositional ores range from 2.2‰ to 7.0‰. The ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁶Pb/²⁰⁴Pb ratios of ores range from 38.19 to 38.53, 15.581 to 15.641 and 18.058 to 18.710, respectively. According to the isotopic data, it is considered that the ore-forming materials were derived from the crust and the upper mantle. Studies show that the Shuangpengxi ore deposit might be a skarn gold deposit related to hypo-and mesothermal processes and belongs to the acid and intermediate-acid magmatic activities of Indo-Chinese and Yanshanian period.