Abstract: In order to solve a high consumption, poor dispersion and other problems of the hydrocarbon oil as the collector of the coal slime floatation, the kerosene, 2-octanol, water an d surfactant were applied to successully prepare a homogeneous and transparent microemulsion with a certain percentage combined under the normal temperature and a mechanical mixing.With the drawing of the pseudo-ternary phase diagram, a best effect of the microemulsion was obtained when the ratio of the surfactant and 2-octanol was 1. 5m. The microemulsion and kerosene were applied to the floatation tests on two coal slime. The test results showed that as for Tunlan coal, the optimum floatation perfect index of the microemulsion would be 2.90% higher than the kerosene and total consumption of the microemulsion would be 25% lower than the kerosene. As for the steam coal from Majialiang Mine, the microemulsion could have a high recovery rate of the flammable liquid and the kerosene could not have. When a same recovery rate of the flammable liquid reached, the total consumption of the microemulsion would be less 50% lower than the kerosene. Due to 2-octanol existed, the adding operation of the foaming agent could be omitted.