Abstract: In order to maintain the purification effect of slow decarburization in the process of the mine dewatering treatment and stabilize the pH value of wastewater intermediate treatment pool，the three－impulse control method based on the feed，effluen and flow disturbance was proposed by analyzing and probing the influence factors of the water level of the intermediate treatment pool，in addition，the system model of the water level of the intermediate treatment pool and the three impulse simulation model in Simulink were established．The simulation results showed that the three－impulse PID control method can eliminate the disturbance within 10 s，the time was reduced by about 290 s as compared with the single impulse method，the disturbance of the water volume was just a few tens of milliliters，and the pH value of the intermediate pool was stabilized to a great extent．