Based on improving the level of mine water recycling,in-situ utilization process and key technology of mine water underground treatment is discussed. After treatment,mine water is mainly used for underground fire sprinkler,coal mining equipment cooling and hydraulic support.The conventional mine water underground treatment process is summarized as follows: pool→elevator pump →sedimentation tank → fine sand filter →utilization.The filter exchanged manganese sand of fine sand,can be used for mine water with high content of iron and manganese.Dual water supply should be taken into full account in the utilization of underground mine water with high-TDS,and advanced desalination treatment is needed with a small amount of water for hydraulic support.The up-flow expanding filtration of neutralization process is feasible for acid mine water underground treatment.It concludes that the key technology of mine water underground treatments are using the underground space scientifically,settling the safety explosion-proof technology and developing modular movable underground treatment devices.