Numerous species and their fundamental reactions are involved in non-thermal plasma (NTP) hue gas cleaning kinetics, but only a few species and their reactions are important. In this paper, the CSTR simulation is utilized to analyze the NTP processes so as to establish the kinetic equations in a logical manner. In addition, by comparing the reaction rates of different species, it is found that only three kinds of reactions (positive ion charge transfer, metastable reactions and radical reactions) are significant for denitrification and desulfurization. Thus the whole set of kinetic equations can be divided into three subsets, each of which corresponds to one kind of reaction. Furthermore, almost all the characteristic times of the reactions of interest are much shorter than the practical treatment time. So, the NTP processes are considered to reach their stationary states. Solving the stationary kinetic equations and calculating the related reaction rates, the main species and their main reactions in four concrete cases of NTP denitrification and desulfurization are picked out. Effects of different conditions on NTP denitrification and desulfurization are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.