Abstract: Using the content of (-)-epicatechin-(4β-8)-(-)- epigallocatechin 3-O-gallate (1), the main degradative product of polymeric proanthocyanidins (PPC) from Chaenomeles cathayensis with tea polyphenols (TP) as an indicator, the effects of reaction temperature, reaction time, PPC/TP ratio and HCl concentration on the content of 1 were investigated by single factor experiment, and the degradative process was opyimized by response surface methodology. The results showed that the optimum degradation condition of PPC were established as 70 ℃ of reaction temperature, 81.5 min of reaction time, 1.5:1 of PPC/TP ratio and 1% of HCl concentration. Under this optimal condition, the actual content of 1 was 601.093 g/mL that was close to the theoretic value (606.103 g/mL), indicated that the response surface method to optimize the degradative process of PPC from C.cathayensis was feasible.