The invention discloses a 
coal mine water underground purification treatment method which comprises the steps of carrying out 
precipitation treatment on 
coal mine water underground for 
solid-liquid separation and carrying out oil-water separation treatment so as to remove suspended matters and oil 
dirt in the 
coal mine water. The mine water enters a water pond to reach the bottom of the water pond through a water inlet 
pipe and then is discharged uniformly from a water distribution area, after 
solid-liquid separation and oil-water separation are carried out by a 
silt removal-oil removal device, suspended matters precipitate and then enter a 
silt discharge device, oil 
dirt is discharged through an oil collecting 
pipe and purified mine water is discharged through a water outlet 
pipe. According to the method, used equipment is simple in structure, low in cost and arranged underground, so that the defects of larger occupied area, environment 
pollution and the like of ground treatment are overcome; in addition, by adopting the method provided by the invention, the technical problem that an oil removal measure does not exist in the conventional mine water purification treatment is solved, the removal efficiency of suspended matters and oil 
dirt in the mine water is high, the oil removal effect is obvious and the 
purified water reaches reusing or drinking standards.