Reaction kinetics of ethanethiol oxidation with potassium permanganate in water was studied, and the effect of ethanethiol oxidation in raw water under coagulation condition has been investigated. The results showed that the oxidation reaction of ethanethiol by potassium permanganate was very efficient, the removing effect could be more than 90%. The rate of ethanethiol decomposition by potassium permanganate in aqueous solution followed second-order kinetics. When potassium permanganate was excessive, pseudo-first-order rate and concentration of potassium permanganate followed the equation: k' = 0.025 [KMnO4] - 0.008. And then, the second-order reaction rate constant was k = 0.025 L/(min x mg). The removal of ethanethiol in raw water by potassium permanganate under coagulation condition was poorer than in pure water condition, So predicted concentration of potassium permanganate was lower than real concentration.