Abstract: The 3000-meter scientific drilling in south Hunan is located in the northwest of the Baoshan Cu-Pb-Zn ore field, and aims to improve the deep metallogenic model and prospecting clues of copper deposits through deep exploration.A 35.02-meter copper orebody was discovered by this scientific drilling at the depth interval of 1664.82~1699.84 m, with the mineralized element Cu reached the industrial grade, and Ag-Au-Ga-Se met the standard of comprehensive utilization.In order to reveal ore genesis of the deep Cu orebody, this study conducted Re-Os isotopic dating and sulfur isotopic analyses.The whole-rock Re-Os age of the copper ores was dated at 159.1±1.1 Ma, which is consistent with the emplacement age of the ore-associated granodiorite and the ore-forming age of the Cu-Mo orebody at shallow depths, indicating that they represent products of the same metallogenic system.The sulfides of the copper ore can be divided into two generations, with the coarse-grained pyrite at the early stage, while the fine-grained aggregates of pyrite, chalcopyrite, arsenopyrite and siderite at the late stage.The δ³⁴S value of the early-stage coarse-grained pyrite(5.97‰ in average)is slightly higher than that of the granodiorite, indicating that the early-stage hydrothermal fluid extracted a small amount of sulfur from the carbonate formation.However, the δ³⁴S value of the late-stage fine-grained pyrite(3.79‰ in average)is approximately similar to the granodiorite, indicating that the ore-forming fluid that responsible for chalcopyrite deposition is a post-magmatic hydrothermal fluid, which was not affected by the carbonate formation.Our results show that the prospecting potential of deep copper deposits below 1.5-kilometer depth of the Baoshan ore field is of great importance, with the distribution of orebodies controlled by the structural fracture zone in carbonate formation and associated with granodiorite.Magnetic anomalies are important prospecting clues, while skarnization is a sufficient but unnecessary clue that signals the distribution of copper orebodies.