In order to achieve safer operating conditions of styrene polymerization process and effective inhibition of runaway reaction, computational fluid dynamics (CFD) technology is applied to simulate the thermal polymerization of styrene. A three-dimensional geometry model of the stirred reactor is established with a tool of SolidWorks. The computational model is carried out with a commercial CFD code (FLUENT). The effect of the viscosity, the impeller speed, the temperature probe location and the diluent addition location are investigated. The simulation results indicate that the three-dimensional model is useful for revealing the distribution of temperature and divergence of thermal runaway and inhibition process on the thermal polymerization of styrene. (C) 2016 Elsevier Ltd. All rights reserved.