Abstract: In order to improve Shenfu coal water slurry( CWS) concentration and overcome the preparation problems due to the bad coal properties such as low ash and sulfur content,high internal water,the ultra- fine Shenfu coal fines was added to the CWS according to the particle gradation theory. The optimum proportion of different particle size and ratio of two additives were optimized via dry CWS preparation process. The influence of different size ultra- fine Shenfu coal fines on viscosity and stability of CWS was researched. The results showed that,when the mass ratio of TJJ1 and TJJ2 was 4 ∶ 1,the dispersity of CWS was the best,When the mass ratio of W125 ~ 200 and Wd50 = 12μmand Wd50 = 6. 5μmwas 40∶ 60∶ 40,the concentration of CWS was about 70%,the viscosity was below 1200 m Pa·s,the stability was B which met the industrial requirements.