Abstract: A hydrophobic ion complex was formed by the reaction between methylene blue and saccharin sodium salt in H2SO4 medium,and the complex was quantitatively extracted with chloroform.Based on these facts,a new method for the determination of saccharin sodium salt in food by spectrophotometry method was proposed.Linear relationship between the values of absorbance and mass concentration of saccharin sodium salt was kept in the range within 15 mg·L-1 at room temperature and with addition of 2.5 mL of 0.2 mol·L-1 H2SO4 and 2.0 mL of 0.04 mol·L-1 methylene blue solution.The detection limit (3s/k) of the method was 0.11 mg·L-1.The proposed method was applied to the analysis of several kinds of food,the values of recovery was found in the range of 100.1%-114.0% with RSD′s (n=6) less than 5.0%