The relationship between the reduction characteristics and molecular structure of 87 chlorinated aromatics including naphthalenes, biphenyls, benzenes and phenols was studied by using quantitative structure-property relationship technique. The result indicated that there was significant correlation between reduction potential and the energy of the lowest unoccupied molecular orbital and the number of chlorine atoms in molecule. The study threw more light on the nature of reduction process, and provided valuable basic data for designing and optimizing treatment process.