Anthocyanins are relatively abundant in vegetables and fruits,which have potential positive health effects. The role of anthocyanins as food coloring agents becomes very important because they can provide attractive bright color of many food products. Nevertheless,the instability of natural anthocyanins was a big obstacle for its usage in food as colorants. The stability of the red radish anthocyanins is significantly improved by modified esterification of the colorant. Usually,the red radish anthocyanins was composed of several components of similar structures. The major methods for determining the structures of anthocyanin colorants involve chromatographic techniques such as TLC,HPLC and HPLC-MS,which are very useful in separation and identification of the components of anthocyanins However,compared to the spectroscopic method,the chromatographic methods are usually complicated and time-consuming during separation and analysis. In the present paper,the authors seek to establish a new,rapid and economic method for the analysis of structural change before and after esterified modification of anthcyanins in view of unique macro-fingerprint characteristics of infrared spectroscopy,which could reflect the whole change of complicated mixture system. The anthocyanins from red radish was esterification-modified by reacting with succinic anhydride,and the natural and modified anthocyanins were detected by FTIR. The results showed that carbonyl of succinic anhydride was connected with the hydroxyl in glucosyl rings of anthocyanins to form new esterified anthocyanins,which are more stable than the natural one and present attractive bright color as usual.