the wastewater from coal dressing has high fine particle which is difficult to naturally subside. This paper analyzes the action mechanism of promoting settling of fine particle in coal dressing wastewater by use of suitable coagulant and flocculate. Through testing, reagent ratios of coagulant and flocculate have been selected for accelerating the settlement of coal dressing wastewater and lowering thickness of overflow. The practical application has shown that the method is simple, can obtain good results and help to realize clear water wash coal and closed circuit the circulation of washing water.