Abstract: In view of the great influence of No. 2 coal seam mining in Yangchangwan Mining Area on the overlying rock aquifer (from the bottom sandstone section of Zhiluo Formation to the roof sandstone aquifer group of No. 2 coal seam and the quaternary phreatic aquifer group),in order to find out the hydrochemical characteristics of groundwater in the mining area and the source of mine water inrush,15 water samples were collected. The Piper three-line diagram,Gibbs diagram and ion ratio method were comprehensively used to analyze the conventional hydrochemical components of groundwater in Yangchangwan Mining Area,and the cluster analysis and fuzzy evaluation method were used to identify the source of mine mixed water. The results show that the TDS of each aquifer is generally high and increases with the increase of buried depth. The main cations are K⁺ and Na⁺,and the anions are mainly Cl^- and SO₄^2-. The Quaternary pore phreatic aquifer is Na-SO₄ type,and the sandstone aquifer at the bottom of Zhiluo Formation and the mine mixed water quality type are Na-Cl type. The hydrochemical componentsIn the Zhiluo Formation aquifer,K⁺ and Na⁺ mainly come from the dissolution of silicates. In the mine mixed water,K⁺ and Na⁺ originate from the dissolution of silicates and salt rocks. In the Quaternary aquifer,K⁺ and Na⁺ mainly come from the dissolution of salt rocks. The source of mine mixed water mainly originate from Zhiluo Formation aquifer,with an average proportion of 93. 23%,and only a small part originates from the Quaternary aquifer,with an average proportion of 6. 77 %. of each aquifer are mainly affected by evaporation and concentration,and are basically not affected by atmospheric precipitation.In the Zhiluo Formation aquifer,K⁺ and Na⁺ mainly come from the dissolution of silicates. In the mine mixed water,K⁺ and Na⁺ originate from the dissolution of silicates and salt rocks. In the Quaternary aquifer,K⁺ and Na⁺ mainly come from the dissolution of salt rocks. The source of mine mixed water mainly originate from Zhiluo Formation aquifer,with an average proportion of 93. 23%,and only a small part originates from the Quaternary aquifer,with an average proportion of 6.77%.