Abstract: In order to tackle the problems encounted in the operation of the washery’s coal slurry treatment system,test is made on the sedimentation characteristics of the coal sample based on result of analysis of the tendency of coal samples collected from different coal seams and mixed samples to undergo size degradation in water.Based on test result,the scheme for optimization of the said slurry treatment system is proposed.Test result indicates that: the gangue material in raw coal of seam 2-2 and that of seam 3-1 differ with each other in degree of degradation,with the former being higher in degradation degree;for blending of coal,the raw coal from seam 2-2 should not be too high in proportion; and the slurry settling effect can be improved through the use of MgCl₂ as coagulant and anion polyacrylamide as flocculants,and through timely adjusting proportioning of agents according to coal blending ratio.