Abstract: On the basis of an analysis of the property of the Zhengning coal,an investigation is made into the effect of the ratio of additive and size consist on the property of the coal water slurry prepared with the Zhengning coal. Investigation indicates that when the additive and power coal are in ratios of 0. 8% and 60%-70% respectively,the slurry thus prepared has a mass fraction of 64. 3% and a viscosity of 1000 m Pa·s,which is up to the industrial coal water slurry preparation standard. Whereas,the test on blending coal shows that when the Zhengning coal and Huanxian coal are blended at a ratio of 3∶ 7,the slurry prepared has a mass fraction reaching 68%,about 4 percentage points higher than the slurry prepared with only Zhengning coal,and a water separation rate of 10. 2%.