Abstract: A highly sensitive and simple fluorescence quenching method has been developed to determine the iodate(IO₃^-)with fluorescein isothiocyanate as the fluorescent reagent (λ_ex=487 nm,λ_em=517 nm).IO₃^- reacts with potassium iodide giving iodine(I₂)which then reacts with fluorescein isothiocyanate to produce a non-fluo-rescent compound,thus the fluorescence intensity of the system is quenched.The linear calibration range is 2～8μg/L.The detection limit for IO₃^- is 0.74μg/L.The proposed method has been used to determine iodate in table salts with satisfactory results.