Abstract: In order to understand the characteristics of coarse slime rod- grinding and flotation process, improve the economic and technical indicators of coarse sli me repreparattion, the paper took the tailing of TBS from Dawukou- Jinneng Coking Coal Preparation Plant as a study object. Firstly, a series of grinding experiments w ere conducted in laboratory, the best slurry concentration, medium composition, mill speed and medium fling rate was determined, and then by adjusting the grinding ti me, five groups of different particle size and dissociation products were obtained. The result showed that the product with 12 min grinding time had more appropriate siz e composition and better dissociation, by repreparation flotation could get clean coal with the ash content 12. 92% and the production rate of the cleaned coal would be 33.89%. In the analysis of density and particle size of floatation concentrate, middings, tailings, part of slime dissociation was inadequate, floating ability of coarse slim e of low ash too poor, resulting low recovery rate, high ash slime by entrainment into the high coal ash.