Based on the UV-Vis absorption characteristics of preservatives and partial least squares variable selection method,the concentration forecasting model of benzoic sodium and sorbic potassium mixture solution was studied.The ultraviolet absorbance spectra of these complexes were examined,and the results indicated that the response signals and concentrations presented good linearities in the ranges of 0.1-16.0 mg/L for benzoic sodium and 0.1-6.0 mg/L for sorbic potassium.The detection limits were 0.05 mg/L for benzoic sodium and 0.01 mg/L for sorbic potassium.The reported model was applied in the simultaneous determination in food samples such as drinks,wine,cake and preserves without any preliminary chemical separation.The relative standard deviations were less than 10% and the recoveries were in the range of 82%-107%.The detection data are consistent with those of the national standard method.