Abstract: The rheological properties of lignite washery tailing suspensions (LWTS) were studied in this paper through pipeline transportation using Q-DP method. The rheological properties were modified based on the modified Mooney method to obtain the true rheological properties of LWTS. Moreover,the effect of mass concentration on the wall slip and rheological properties of LWTS were also analyzed. The results show that only when wall shear stress exceeds the critical wall shear stress can wall slip occur. The critical wall shear stress increases with the increase of concentration. Three concentration ranges of LWTS are obtained according to their differences in rheological aspects,i. e. ,low con- centration zone (39. 24% -41. 48% ),middle concentration zone (42. 32% -43. 33% ) and high concentration zone (44. 81% -46. 21% ). The viscosity of LWTS also increases with the increase of concentration.