The emulsion polymerization of MMA was explored for the BDE/CuCl coordinated catalyst. The M-n of PMMA linearly increased both with increasing the monomer conversion and the proceeding polymerization time, which means that the MMA polymerized in "living"/controlled characters with zero order kinetics under BDE/CuCl-catalyzed emulsion conditions. The apparent polymerization rate constants of MMA were k([MMA] = 3.0M) = 0.765 mol/min, k(app)([MMA] = 1.8M) = 0.760 mol/min at 80degreesC, while k(app)([MMA] 1.8M) = 0.228 mol/min at 50degreesC, respectively. Slight differences of polymerization results were obtained when emulsifier lauryl phosphate (ADP) and Polyoxyethylene nonyl phenyl ether (OP-10) were adapted in the polymerization. Based on the "coordinated radical cage" mechanism proposed particularly to the BDE/CuCl catalyzed polymerization, reversible equilibrium between common free radical and the coordinated "living" species should exist in this system. Increasing the amount of catalyst must affect the fast equilibrium between those two species, thus, also affecting the relative content in the emulsion circumstance. Therefore, PMMA, with bimodal molecular weight distribution, was achieved through this approach. The formation of PMMA with bimodal distribution was affected by concentration of catalyst and polymerization temperature.