Abstract: The determination of iodine in food is important due to the function of iodine of keeping body health.A rapid,simple and sensitive catalytical kinetic method is developed for the determination of iodine.The method is based on the inhibitory action of iodide ion on the decoloration of methylene blue oxidized by potassium bromate catalyzed by sodium thiosulfate in nitrate acid medium.The linear ranges of determination are 0.01-0.2 μg mL^-1,and the detection limits are 0.0062 μg mL^-1.The developed method has been used for the determination of micro amounts of iodine in kelp and lavel with satisfactory results.