Abstract: The water treatment device for emulsion preparation in fully mechanized mining face mostly adopts manual or hydraulic control mode for water preparation and filter element cleaning. It is unable to monitor water production data and device working status in real-time. It has low degree of automation, complex operation and heavy maintenance workload. By analyzing intelligent control requirements of the water treatment device in underground coal mine, a thermal redundancy scheme of double controllers is designed. The scheme has two controllers that are used to realize the water preparation and automatic cleaning functions of the water treatment device respectively. Based on the scheme, an intelligent control system for water treatment device in underground coal mine is designed. The KXH12B mine-used intrinsically safe controller is used as the core control unit to collect the data of water tank level sensor, pressure sensor, flow sensor and conductivity meter. The water treatment device operation status is monitored in real-time. The two controllers work in a master-slave mode. The master-slave controllers realize control functions of automatic water preparation and automatic cleaning respectively. When the main controller fails, its water preparation function can be automatically switched to the slave controller. This ensures that the water for emulsion preparation in coal mine is not affected. The test platform is built to test the system, and the results show that the system realizes control functions of automatic water preparation, automatic cleaning and data monitoring. The system also realizes the hot-switching function of master and slave controllers. The system has been applied to the water treatment device in a coal mine. It runs stably and reliably, and realizes unattended operation of the water treatment device in coal mine.