The objective of this project is to explore the iron-catalyzed oxidation performance of 2-chloroaniline (2-ClA) under different illumination wavelengths. UV irradiations with different wavelengths at 254, 300, 350, 419 nm, corresponding to UVC, UVB, UVA, and UV-visible banding, respectively, are chosen as the light sources. The oxidation of 2-ClA by different iron-catalyzed oxidation processes, with or without the presence of ultraviolet light and oxalate, was investigated and compared. The performance was compared by means of the initial decay rate and the overall removal percentage. To achieve an in-depth understanding, all the feasible combinations and/or blank systems were investigated: UV radiation only, UV/H2O2, H2O2/Fe2+, H2O2/Fe3+, UV/H2O2/Fe2+, UV/H2O2/ Fe3+, UV/H2O2/Fe2+/ oxalate (Ox), UV/H2O2/Fe3+/Ox. The initial 2-ClA decay rates and the total removal percentages generally followed the order of UV254 > UV300 > UV350 > UV419. Among all tested processes, UV/H2O2/ Fe2+ and UV/H2O2/Fe3+/Ox are suggested to be used for the treatment process of 2-ClA, because both processes are very effective in removing 2-ClA in solution over a wide range of wavelengths.