Based on the charge transfer reaction between bisphenol-S(BPS) and borax,a simple and rapid method was developed for the determination of BPS by ultraviolet spectrophotometric method.The results indicated that in water medium,BPS could form charge transfer complex with borax,and its maximum absorption wavelength was 291 nm.The apparent molar absorptivity was 192×104 L·mol-1·cm-1.Beers law was obeyed for BPS in the concentration range of 07-7 mg/L.The correlation coefficient was 0999 6,and the detection limit was 0195 μg/mL.The proposed method was applied in the determination of BPS in samples with satisfactory results.The recoveries for BPS were in the range of 998%-1004% with RSDs(n=5) not more than 05%.