Abstract: The apparent viscosity of coal-oil slurry of Shengli was measured using a high-temperature viscometer. Some factors that affect apparent viscosity change of Shengli coal-oil slurry were studied, such as mass fraction, particle size distribution, solvent properties, temperatures, shearing time, shearing rate and solvent swelling. The apparent viscosity of coal-oil slurry was compared in STR and REC from room temperature to approximately 350℃. The results show that Shengli coal-oil slurry is nonNewtonian fluid. Its apparent viscosity decreases firstly, then keeps invariability, finally increases with temperature rising. The temperature range for constant apparent viscosity and temperature for the apparent viscosity beginning to increase depend on solid concentrations, particle size distribution and solvent properties.