Abstract: NH₃,O₂,N₂ and vapor are commonly used gases to generate N,H,O radicals.In this work,NH₃+Ar,O₂,dry air and humid air were selected as working gases of radical sources to research NO removal.It was shown that stable corona could be formed by different radical sources. However, they had certain effect on discharge characteristic. The conversion rate of NO into NO₂ by air and oxygen was obviously higher than that by NH₃+Ar.NO₂ was easy to be absorbed by lye and greenhouse gases,N₂H and N₂O, were produced when adding NH₃+Ar.Therefore air and oxygen were better radical sources.When air was injected into the electrode,NO removal efficiency was a little worse than the case of oxygen but almost the same as the case of NH₃+Ar.However, considering safety and economy, air has a better prospect of application.A few water vapor was helpful to improve NO removal.Humid air was the best choice among NH₃+Ar,O₂,dry air and humid air.