Two coal samples of similar rank were chosen from Australia and China to investigate the differences in Coal-Water Slurry (CWS) made from them.The effect of ash content and particle size gradation on these properties was also studied.Different grinding times were used when grinding the two coals and particle size analysis of these ground coals was used to select samples with a "double-peak" particle size distribution.All the "double-peak" samples were used to prepare a CWS.The concentration,viscosity,fluidity,and stability of each CWS were measured.The results show that the properties ofa CWS prepared from a coal sample with a "double-peak" size distribution are better than those CWS prepared from samples with a mono-modal particle distribution.The ash content of Australian coal is 21.72％ higher than the ash content of Shenhua coal.The highest coal concentration in slurry from the Australia coal is 11.01％higher than in CWS from the Shenhua coal.The fluidity and stability of the CWS prepared from the Australian coal are both better than the fluidity and stability of slurry prepared from Shenhua coal.High ash content in the Australian coal improves the pulping results of a CWS made from it.