In the coming decades, polyvinyl chloride (PVC) is considered as the common plastics in petrochemical industries due to its high potential application. To make PVC's, monomers were produced firstly which is called vinyl chloride(VCM). This process is done in the ethylene dichloride thermal (EDC) cracking reactor within the temperature profile range of 680-758 °K and the pressure drop of 25*105 Pascal. The objectives of this comprehensive study is to simulate 2D of thermal cracking reactor with FLUENT software and compare with an industrial reactor to obtain an optimum EDC conversion factor. Furthermore, the crucial parameters and their profound impact on the calculation of EDC conversion factor were taken into the consideration to spouse the importance of each parameter. Consequently, EDC conversion factor with the percentage of 52.69 has a good agreement with industrial data.