Abstract: Abstract: the coal mine water treatment plant filtration device was studied and introduced the structure of filter device. The four stage filtration device was designed to achieve the hydraulic system of forward and reverse flushing in continuous water supply condition; the hydraulic motor was provided in the appropriate speed to gap filter and fiber filter L, R washing tank in hydraulic system. AMEsim software was used to simulate the design of hydraulic system and hydraulic oil system, analysised of fiber filter tank L、R and folding filter flow-time curve, analysised of hydraulic motor speed-time curve; obtained the conclusion: the design of the hydraulic system and hydraulic oil system meet the requirements of using.