Abstract: The purification effect of coal mine groundwater reservoir on mine water mainly lies in the water-rock coupling between the rock mass and mine water.This paper systematically reviews the research methods of water-rock coupling in coal mine underground reservoirs, and presents the characterization methods of water quality and physicochemical properties of rock samples.It employs static simulation, dynamic leaching, cycle purification simulation and other tests to explore the purification regulation of mine water in coal mine underground reservoir, uses numerical simulation to obtain the selective adsorption trend of ions in the reaction process, and combines Piper three-line diagram, Gibbs model and correlation analysis to reveal the mechanism of water-rock coupling.The purification effect and research progress of suspended solids, specific ions and organic matter in coal mine underground reservoirs are discussed.The paper shows that underground reservoir of coal mine has a certain purification effect on mine water, and the purification effect of specific ions is mainly related to filtration and adsorption.Three research directions of coal mine underground reservoir purification technology in the future are proposed: ①developing large-scale and low-cost treatment technologies for underground mine water based on water-rock coupling purification, ②developing a "three-in-one" water quality control technology for coal mine underground reservoirs coupled with multiple water treatment technologies, and ③exploring the underground storage and resource utilization technology of concentrated salt wastewater for the future studies of water-rock coupling.