Abstract: The 3⁻¹ coal in Xinjie Mining Area is buried deep, and the thick Zhiluo Formation and Zhidan Group aquifers are the main water-filled aquifers, and the hydraulic correlation between surface water and aquifers affects water inrush in the mine. Based on the hydro-chemical characteristics and the test of pumping (discharging) water, the vertical hydraulic connection of aquifer was carried out. The results of hydro-chemical tests and Piper chart show that the salinity of surface water, Zhidan Group and Zhiluo Formation aquifers increases gradually, and the hydro-chemical type changes from HCO₃−Ca type to SO₄−Na type. The analysis of Gibbs diagram and SOM model show that the ions in surface water mainly come from the weathering of carbonate rock and silicate rock, the ions in Zhidan Group aquifer and Zhiluo Formation aquifer mainly come from silicate rock and gypsum, and oxidation of metal sulfides is also exist in Zhiluo Formation aquifer. The controlling factor of hydro-chemical characteristics changes from water-rock interaction to evaporation concentration, the Zhidan Group aquifer and Zhiluo Formation aquifer have strong cation alternation. The Cl⁻ index quantitatively indicates that the hydraulic correlation degree between surface water and Zhidan Group aquifer, Zhidan Group and Zhiluo Formation aquifer is 0.28, which belongs to the medium degree of hydraulic correlation. The hydraulic correlation degree between surface water and Zhiluo Formation aquifer is 0.43, indicating that hydraulic correlation is weak. At the same time, the surface pumping test of Zhidan Group aquifer and the underground dewatering test of Zhiluo Formation aquifer further indicate that there is a hydraulic connection between Zhidan Group aquifer and Zhiluo Formation aquifer. Zhidan Group aquifer and Zhiluo Formation aquifer are the main water-filling aquifers of mine.