Abstract: The water conduction fissure formed by longwall mining of coal mine leads to the destruction of groundwatersystem,resulting in the contradiction between the abundant water in goaf and the shortage of surface waterresources,thence reasonable protection and utilization of mine water is of great importance to the safe productionof coal mine and the construction of ecological civilization in mining area.Using the goaf as an underground reservoirand taking advantage of the strong capacity of broken coal and rock mass in the goaf is an important means torealize the treatment of mine water pollution and resource utilization.The water quality of most mine water in China ispoor,the total dissolved solids are high,and the treatment is difficult,so the water⁃rock purification of broken coal androck in goaf reservoir is conducive to the efficient in⁃situ treatment and utilization of mine water.At present,a series ofstudies have been carried out around the water⁃rock interaction of broken coal rock in goaf,including sample collec⁃tion,sample detection,simulation experiment and result analysis.Sample collection and detection is the premise of thestudy of water⁃rock interaction, which involves the basic characteristics and change rules of mine water and coalrock mass.The simulation experiment and result analysis mainly explore the action mechanism of various influencingfactors.The research on water purification mechanism of reservoir in mining area mainly focuses on water⁃rock interac⁃tion.The experiments of static simulation,dynamic dripping simulation and circulating water immersion provide usefulreference for exploring the water purification mechanism of water⁃rock interaction.Combined with the basic theoriesof hydrogeochemistry,rock mineralogy and water chemistry,a series of possible water⁃rock interactions in goaf,such asleaching ⁃ precipitation,adsorption ⁃ resolution,redox and mixing,are elucidated.The purification effect of the goaf res⁃ervoir is better for the concentration of suspended solids in mine water,followed by the purification effect of COD,while the purification effect of total hardness,TDS and total alkalinity depends on the mineral composition of bro⁃ken coal and rock mass in the mined⁃out area,water storage time and other factors,and the deterioration of the aboveindicators may occur. However,the influence factors of the design in the current indoor water⁃rock simulation testscheme are relatively simple,and the relevant data such as hydrodynamic field,temperature field and oxygen concen⁃tration in the study area are lacking.On this basis,the research and development direction of water purification technol⁃ogy for goaf reservoir in coal mine is proposed.Under the principle of clarifying local policies and water quality andquantity,in⁃depth research is made from the perspectives of goaf′s own conditions and external environment to en⁃sure the stability,economy and safety of water purification technology in goaf reservoir.