This research presents an advanced multi-scale computational fluid dynamics (CFD) model based on the ‘multi-phase particle-in-cell coupled with the population balance equation (MP-PIC-PBE)’ method to predict the stationary continuous stirred tank reactor for methyl methacrylate suspension polymerization. The developed CFD model can realistically simulate the flow patterns of the free-flowing particles and the continuous carrier phase based on the Euler-Lagrangian frame and can track the change in particle size based on PBE. In particular, the model can predict the polymer properties by free-radical polymerization in a parcel through the method of moment equations. To validate the suggested CFD model, the simulation results are compared with the reported experimental data in the literature. Various case-studies are then conducted to investigate the effect of different blade angles (pitched blade angles of 30˚, 45˚, and 60˚) of the impeller on the mixing, the particle size change, particulate flow pattern, and polymer properties. The simulation results demonstrate the phenomena that the low-density particles rise in the larger density solvent by buoyancy and that the higher the blade angle, the smaller the resulting particles due to a higher rate of breakage. It is also found that the particulate flow is well mixed with a 45˚ blade angle.