Abstract: Based on the analyzing the situation of primary coal slurry treating system in Dongpang coal preparation,determined the technical renovation scheme for deep cone thickener,that is combined the technology of deep cone thickener with the inclined plate depositing poor,so that reformed the one stage thickening in primary system into two stage thickening.After the reformation,the low quality coarse slime recovered into the middlings,that increased the thickening and depositing efficiency of coal slime,ensured the coal washed with fresh water,obtained significant economic benefits.