Abstract: In order to achieve high efficiency of flotation of bituminous coal slime, swill-cooked dirty oil, Gemini cationic surfactants (31709 surfactants) were used as main raw materials in synthesis of a new type of highly efficient microemulsion collector (DG-1), test result illustrated that the volume fraction of microemulsion droplets were more than 98% and had good stability. Flotation experiments and cost-benefit estimates demonstrated that the flotation performance and clean-coal profit of DG-1 were all better than 0# diesel when the dosage of collectors was same, the improvement of DG-1 flotation performance was closely related to the adjunction of 31709 surfactants. X-ray photoelectron spectroscopy (XPS)，contact angle meter and microiontophoresis apparatus were used to investigate that 31709 surfactants promote flotation performance of DG-1, the results illustrated that 31709 surfactants efficiently cover oxygen-containing functional groups, inducing the reduction of oxygen content on coal slime surfaces and the enhancement of the hydrophobicity of coal slime; the contact angle of coal slime increased about 12° after adsorbing 31709 surfactants, which further verified the enhancement of hydrophobicity of coal slime after adsorption; meanwhile, 31709 surfactants promoted the dispersal of coal slime and increased the stability of coal slime, which were favorable for the improvement of coal slime flotation.