Abstract: The rheological behavior of slurry of coarse polypropylene particles can not be determined by means of ordinary viscometers due to its kinematic unstability and "the wall effect" occurred in the measurement of viscosity. After ascertaining the slurry of polypropylene to be Bingham liquid by using Brabender viscometer the workers determined the plastic viscosity and yield value from the correlation between agitation power number and Reynolds number of Bingham liquid in the chemical vessel with ribbon agitator. As a result, the basic data of heat transfer, mixing and agitation in the liquid bulk polymerization of propylene were provided.