Coal water slurry（CWS）is a heterogeneous solid-liquid suspension system. Rheological tests were conducted using coaxial cylinders, and it was found that during the testing process, coal water slurry experienced significant solid particle settling, especially in the low shear rate range. Therefore, based on the principle of "stirring viscosity measurement", this article uses a paddle type double arc measuring rotor to maintain a relatively uniform mixing state of solid and liquid phases. The relevant rheological parameters of low shear rate coal water slurry are measured and characterized, and the effects of concentration, particle size, additives and other factors on the viscosity of coal water slurry are explored. The results show that within the low shear rate range, the particle size of coal water slurry remains constant, and the higher the mass concentration, the greater the viscosity; When the mass concentration is constant, the coarser the particle size, the greater the viscosity; After adding dispersants, the viscosity of coal water slurry significantly decreases, while the viscosity of coal water slurry significantly increases after adding stabilizers.