Abstract: According to the carrier flotation theory,this paper provides a method of using flotation cleaned coal as au- togenous-carrier to improve the flotation efficiency of coal slime. This method tends to fix the problem that because the ash of flotation cleaned coal is often higher than the required ash and the yield of clean coal is low,the production op- eration is difficult for the coal slime containing fine particles and high ash clay. Moreover,the results show that the coal slime flotation effect can be significantly improved by this method. Experiment results illustrate that with the increase of the amount of autogenous-carrier,the clean coal yield,the flotation perfect index and the tail coal ash are increased, besides the ash of the flotation cleaned coal is reduced. This flotation process has been used to separate the slime from Wuhai and the feedback shows the yield of flotation refined coal increases by 7． 11% , ash content decreases by 1.14% and the improvement index of flotation improves by 7． 25% . Furthermore,the results show the optimum dosage of autogenous-carrier is 10% of the floating slime and the stable flotation effect can be achieved after 3-4 cycles by adding autogenous-carrier. The EDLVO theory has been studied and the results show that the hydrophobicity of the cleaned coal itself and the adsorption of the collector on the coal particle surface lead to the hydrophobic force which encourages the fine coal particles are adhered to the coarse particle carrier and the hydrophobic flocculation occurs be- tween the fine particles. Finally,the flotation environment and flotation effect were improved.