详细研究了 Ｋ Ｉ Ｏ３、 Ｋ Ｉ与罗丹明 ６ Ｇ 在酸性介质中的显色反应，反应产物之最大吸收波长λｍ ａｘ为 ５６０ ｎｍ ，由此建立了一个简单、快速、灵敏、实用的分光光度测定食盐中添加剂 Ｋ Ｉ Ｏ３的新方法。在最佳实验条件下， Ｋ Ｉ Ｏ３ 浓度在 ０～２ ｍ ｇ／ Ｌ 内服从比耳定律，其线性相关系数 ｒ 为 ０．９９９８ 。所拟方法用于加碘食盐中微量 Ｋ Ｉ Ｏ３的测定，结果与紫外光度法所得结果基本一致。 The color reaction of KI O3, K I with rhodamine 6 G in acidic medium was studied in detail. The maximum absorption wavelength λm ax of the reaction product was 560 nm, and a simple, rapid, sensitive and practical spectrophotometer was established Determination of salt additives K I O3 new method. Under the optimal experimental conditions, the Beer’s Law was obeyed at K 2 O 3 concentration of 0-2 m g / L, and the linear correlation coefficient r was 0.9998. The proposed method was applied to the determination of trace KI O3 in iodized table salt. The results were in good agreement with those obtained by UV spectrophotometry.