Abstract: To develop a cleaner production process of H₂O₂-based chlorine dioxide, this paper presents a study on reaction mechanism and dynamics of the process.It is shown that a complex H2ClO2-ClO₃ exists as an intermediate in the process.A rational reaction process is proposed, which unifies several reaction mechanisms reported by different researchers in a wider range of reaction temperature.A theoretical model of the dynamics is presented, and parameters of the model are experimentally estimated and verified.