Research　of　dissolved　organic　matter　(DOM)　adsorption　by　coal　gangue　was　carried　out.　Coal　gangue　was　from　coal　mine　underground　reservoir　and　was　characterized　by　SEM,　BET,　BJH,　and　XRF.　The　effects　of　the　coal　gangue　dosage,　temperature,　and　initial　DOM　concentration　on　DOM　removal　by　coal　gangue　were　investigated.　Results　show　that　the　coal　gangue　has　a　lamellar　structure　with　well-developed　inter-particle　pores.　The　BET　specific　surface　area　of　the　coal　gangue　was　5.697　m2/g.　A　0.748　mg/g　equilibrium　adsorption　capacity　and　74.78%　DOM　removal　efficiency　were　gotten　under　the　conditions　of　20　mg/L　DOM　concentration,　20　g/L　coal　gangue,　25　℃,　and　12　hours　adsorption　time.　The　DOM　adsorption　by　coal　gangue　can　be　well　described　by　Langmuir　isotherm　and　quasi-second-order　kinetic　model.　The　adsorption　process　was　monolayer　adsorption　and　was　mainly　chemical　adsorption.　The　thermodynamic　analysis　shows　that　the　adsorption　process　is　a　spontaneous　endothermic　reaction.　DOM　removal　performance　and　mechanism　by　coal　gangue　in　high-salinity　mine　water　system　were　deeply　explored.　The　research　results　may　provide　a　theoretical　support　and　technical　guidance　for　safe　storage　of　water　in　underground　reservoir　with　high-salinity　mines　(represented　by　the　Ningdong　mining　area),　and　give　an　insight　for　solving　the　problem　of　water　shortage　in　the　western　coal　mining　areas.　©　2022,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.