Abstract: Aqueous two- phase system was used to extract proanthocyanidins from rapeseed meal.Four extraction parameters including ethanol concentration,ammonium concentration,p H,temperature were optimized based on single factor investigations for achieving yield of proanthocyanidins,the interaction of the respective variables and their influence on the yield were studied by using Box- Benhnken central composite design and response surface analysis theory,a quadric regression equation forpredicting the extraction yield of proanthocyanidins was established.The results showed that better extraction conditions were as follows: ethanol mass fraction of 26%,ammonium sulfate mass fraction of 18%,p H of 2.40,the extraction temperature 39 ℃,Under optimum conditions,the yield of proanthocyanidins was 7.78 mg / g.The study would provide certain data base for the effective utilization and development of proanthocyanidin.