The kinetics of aniline degradation by persulfate processes with iron(Ⅱ) activation at ambient temperature was investigated in this study. With iron(Ⅱ) as initiator, the oxidation reactions were found to follow a biphasic rate phenomenon: a rapid transformation followed by a slow but sustained oxidation process. In the first 30 s, the reaction mainly relies on the persulfate-Fe2+ reaction in which aniline is oxidized rapidly. After 30 s, the aniline was still oxidized but the rate of reaction tended to be slower and the rates were clearly linear-proportional. After the initial fast oxidation, the reactions appeared to follow a pseudo-first-order model.