The analysis of oxidative degradation products of 2,4,6-trichlorophenol (TCP) treated with air ions, which are generated by electric discharge, is reported. Due to the complex nature of the degradation products, a combination of different detection techniques was employed to characterize them. The oxidative degradation of TCP is usually dependent on the treating approaches, and in this system, a stepwise degradation, beginning with the formation of a major product 2,6-dichloro-1,4-benzenediol as well as other minor ones (e.g., 3,5-dichlorocatechol) via substitution, is first proposed through a detailed analysis of GC/MS, etc., though some chromogenic quinones can transiently be present. Furthermore, high dechlorination (53%) was observed for TCP after a 60-min treatment, indicating that air ions can serve as an efficient dechlorination means.