In this paper, acetone iodation was carried out and the Huang method based on experimental results was employed to calculate the effective permittivity of acetone iodation system as a function of temperature and reaction time. The coupled electromagnetic field equations, reaction kinetics equations, and heat transport equation were solved to simulate the microwave heating on chemical reaction. Here, the finite difference time domain (FDTD) method was used. Finally, the calculated results were compared with the measured results to verify this calculation. This method offers high potential applications in the explanation of some specific phenomena in the microwave heating on chemical reactions and instructs the design of microwave chemistry reactor.