Abstract: The problems with the use of traditional collectors involve excessive absorption of collector, depression of floating of ultrafine coal particles, and hence increase of costs of subquent processes because the collectors used have generally a large size of droplets. To deal with this situation, a study is made on the effect of emulsification of collector on slime flotation. Based on the results of laboratory test on different emulsification conditions with a specifically designed emulsifier, flotation test on of the coal samples collected from four different mines is carried out by Huaibei Plant using emulsified collector. Test results show that a best emulsification result can be obtained at an oil-water ratio of 2:1, an agitating speed of 1 100 r/min and an agitating time of 10 minutes; and under these conditions, there can be seen the obtainment of the best comprehensive flotation indicator, a lowest ash value of concentrate product and highest recovery of combustible matter.