Abstract: The rheological behavior of 182 CWS samples was studied using 14 Chinese coals with 12 dispersants. The results show that the CWS rheology of low rank or high ash coal is mainly due to the physical and chemical properties as well as surface structure characteristics of coal. The CWS rheology of high rank coal depends mainly on the structure and property of the dispersants. Generally, when the molecular structure unit of dispersant has large space effect, its hydrophilic and hydrophobic groups are space alternate distribution, it results easily in CWS to exhibit pseudo-plastic behavior. When the dispersant is a length chain polymer, its hydrophilic and hydrophobic groups are linear alternate distribution, it results easily in CWS to exhibit dilatant behavior. Furthermore, the effect of interaction among complex coal particles on CWS rheological behavior has been discussed.