Abstract: According to the low monomer polymerized density of the polyacrylic acid and the high polymerized temperature disadvantages, the polyacrylic acid disp ersant of the coal water slurry was prepared with the acrylic acid glycol ester, acrylic acid, styrene sulphonic acid sodium, methyl acrylic acid, styrene as copolymerizati on monomer, under the temperature of 60 °C, when the initiator n (NaHSO3) : n (K2S2O8)= 5:6, the dosage of potassium persulfate was 8% of the monomer quality, t he dosage of different propyl alcohol of the chain transfer agent was 55% of the monomer quality.Meanwhile the paper investigated the temperature, the dosage of the potassium persulfate, n (NaHSO3) : n (K2S2O8) ratio, the dosage of different propyI alcohol affected to the performances of the dispersant.The modified compound tec hnique could improve the monomer polymerized density with 16.3% and could reduce the polymerized temperature with 40 °C.The slurry preparation tests of three kind coal were conducted with the synthetic dispersant.When the dosage of the dispersant was 0.4% (quantity fraction) of the dry coal and the prepared slurry density was 7 2%, the min apparent viscosity value of the coal water slurry made from Jixi bituminous coal and Matou cleaned coal would be 850 and 670 mPa.s individually.As for th e Baori lignite, when the prepared slurry density was 53%，the min apparent viscosity value of the coal water slurry would be 550 mPas.