The treatment of coal sludge water involves all aspects of the washing process in coal processing plants, which is a systematic and complex project. Each coal processing plant adopts different washing processes and management methods according to the quality of the raw coal to be washed, so there are also differences methods to treat coal sludge water. In Dingji coal processing plant, due to the serious mudification of raw coal and the large amount of secondary coal sludge, the coal sludge water treatment system had a large operating load, and the coal sludge water concentration, flocculation and dewatering treatment were more difficult. The process optimization modification of the raw coal sludge water treatment system was carried out to effectively improve the recovery rate of fine coal and solve the problems of poor flotation effect and high energy consumption through the process optimization of closed washing water circulation pipeline, classifying cyclone and PAM chemical addition.