increase in viscosity), [15] suspension polymerization is one of the most important technologies applied in the poly merization industry. A key consideration in designing a suspension polymerization is to achieve such that desired molecular microstructure and droplet/particle size dis tribution (PSD) of polymers are satisfied. The number average molecular weight (M n ) and polydispersity index (PDI), as the most basic performance indices of polymer affecting the polymer enduse properties, are mainly determined by polymerization kinetics, and the PSD can control some key aspects of operation including suspen sion stability and productivity. Hence, there is a growing demand for studying suspension polymerization kinetics and its droplet/particle kinetics.For a suspension polymerization, two characteristic phases, i.e., the aqueous phase and the dispersed phase, are present. If the dissolved monomer in the aqueous phase is ignored, the polymerization process occurring at the suspension droplets will be considered as a bulk one.In this work, a mathematical model is developed to characterize the batch atom transfer rad ical suspension polymerization (batch suspension ATRP). For the first time, the morphological and molecular properties of particles, as well as their dynamics in methyl methacrylate ATRP can be simultaneously simulated by solving the model that consists of ATRP kinetic equations, moment equations, a phase equilibrium equation for calculating equilibrium monomer dis tributions in various phases, and a particle population balance model. The proposed model is verified using the open experimental data. Based on the verified model, two key operating factors including the ratios of monomer to initiator and water to monomer are studied in order to investigate the batch suspension ATRP kinetics. In addition, the model is also used to predict the droplet/par ticle size distribution. The effects of breakage rate, coales cence rate, and agitation speed on the droplet volume density distribution and the Sauter mean diameter are discussed in details. The simulated results demonstrate that the coupled model can describe the batch suspension ATRP kinetics and its droplet kinetics.