Polyphenol oxidase and anthocyanins with high purity were obtained from Litchi pericarp by modern purification methods. The degradation mechanism of anthocyanins in the presence of (-)-epicatechin and litchi pericarp polyphenol oxidase (PPO) and the effects of the reactant concentration on the anthocyanins degradation rate were studied. The results showed that redox reaction between PPO and (-)-epicatechin occurred firstly and generated lots of (-)-epicatechin oxidation products, which reacted with anthocyanins and resulted in degradation of anthocyanins. Anthocyanins degradation rate was affected obviously by the substrate concentration.