Abstract: According to the adverse influence of the ash content to the dispersed effect of the dispersant in the slime water slurry preparation, a salt resistance mo de polycarboxylate dispersant was designed and synthetised. The performances of the dispersant were investigated with the infrared analysis, the surface potential det ection and the slurry preparation experiment. The study results showed that the polycarboxylate dispersant and the coal sample had a similar structure and had a good fitting. When the dispersant and coal particles integrated, the surface potential of the coal particle would be obviously reduced and the electronegativity would be remar kably increased. When the relative molecule quantity of the polycarboxylate dispersant was 110 000 ~ 170 000, the slurry preparation effect would the be best and mos t stable. In comparison with the wood and naphthalene series dispersants, the slurry density of the coal water slurry prepared with the polycarboxylate dispersant would be about 61%, the slurry would have good flowability and stability and the dispersion effect was the best.