The kinetics of quinoline degradation by O3/UV in aqueous phase was studied in this paper. It was found that the stoichiometric factor for the number of ozone molecule consumed by per quinoline molecule was 1. The second-order rate constants at 15℃ for the direct reaction of quinoline with ozone and that for the reaction of quinoline with. OH were determined to be 51.0 and 7.24×109M-1 s-1, respectively. In O3/UV reaction system, -OH was the more important oxidant to degrade quinoline than ozone. For a comparison, in O3 reaction system, the relative imp ortance of the two oxidants depended on the pH value greatly. To make the degradation of quinoline more practical, improvement of the concentration of. OH is more feasible.