Abstract: Due to the high prices, large dosages, difficult dispersing, poor selectivity and other problems of the present traditional slime floatation reagents, the ultr asonic method was applied to prepare the emulsified diesel collector and to study the hydrophilic and lipophilic balance value, the emulsifier dosage, the oil and water p ercentage, co-emulsifier, the ultrasonic time and other factors affected to the stability of the emulsified diesel.The floatation performances of the emulsified diesel were verified with the floatation experiment.The stability experiment results showed the optimization single factors conditions as follows, the hydrophile-lipophile balance valu e was 13, the quantity rates of the sorbitan monooleate, the polyoxyethylene sorbitan monooleate, the triethanolamine oleic soap and sodium lauryI sulfate were 10 : 5 : 2 : 3 individually to mixed emulsifier, the mixed emulsifier dosage was 1.2% (quantity fraction)，the quantity rate of the diesel and water was 3 : 7, the co-emulsifier n- butyl alcohol dosage was 5% (quantity fraction) and the ultrasonic time was 7.5 min.When the clean coal production rate was the same, the dosage of the emulsified die sel would be only 30% of the diesel.When the dosage was the same, the clean coal production rate of the emulsified diesel would be the same to the diesel, but the ash content of the clean coal would be 0.4% lower than the diesel.