Non-thermal plasmas technology has received considerable attention in the field of air purification characterized by low costs, high removal rate and high energy efficiency in recent years. However, Undesirable byproducts, such as nitrogen oxide, ozone, carbon monoxide, were also formed during the decomposition of toxic air contaminant, which are harmful to the environment and to human health. To eliminate these byproducts completely, a novel air-purification system, consisting of activated carbon fiber(ACF) adsorption filter, non-thermal plasmas reactor, byproduct remover, microwave generator, was constructed and the performance of this system was investigated for treatment of gaseous benzene in a 1 m3 highly tight closed room. The experimental results show that the indoor benzene concentration was reduced by several adsorption/desorption cycles to an almost zero value in 60 min. The benzene adsorbed in the ACF was desorbed by microwave into a 0.05 m3 closed chamber where the concentrated benzene was decomposed completely by non-thermal plasmas reactor. Furthermore, the byproducts produced during the decomposition process of benzene were also eliminated effectively via byproduct remover.