Abstract: To understand the hydrochemical characteristics of surface water and groundwater in the Gongniergai gully of Zhuanlongwan Coal Mine, a comprehensive study associated with hydrochemical analysis and statistical analysis was conducted. The hydraulic connection between surface water and groundwater was investigated. The results showed that the mass concentrations of anions and cations in the surface water and groundwater of Gongniergai gully exhibited the following order: ρ(Na⁺+K⁺)>ρ(Ca²⁺)>ρ(Mg²⁺) and ρ(HCO₃^-)>ρ(SO₄^2-)>ρ(Cl^-)>ρ(NO₃^-). The prevailing hydrochemical types were primarily categorized as HCO₃-Ca and Cl-Na. It is noteworthy that the mean concentrations of major ions in surface water were higher than those in groundwater. The observed water chemistry of surface water and groundwater were primarily influenced by rock weathering and cation exchange processes. The dissolution of carbonate rocks and silicate minerals were identified as the main sources of ions. There was a hydraulic connectivity existed between groundwater and surface water. The hydraulic connection between the Ⅱ-3 coal roof aquifer and the Quaternary groundwater and surface water was relatively weak. Thus, appropriate water prevention and control measures should be implemented when mining operations extend to bottom of the Gongniergai gully or the water logged area.