Abstract: To study the structure of proanthocyanidin in zijuan tea and its inhibitory activity on the α-amylase. The proanthocyanidins of Zijuan tea were extracted and purified,and the purity of proanthocyanidins was 93% by vanillin sulfuric acid method. Then,UPLC-ESI-MS was used to identify the components of procyanidins,initial identification of at least 3 monomers(including(E)C,EGC,EGCG)and 7 procyanidins oligomers(including proanthocyanidin polymer m/z 761,m/z 745,m/z 729,m/z 865,m/z 881,m/z 609,m/z 593),and its inhibitory activity on α-amylase was studied,which showed that the procyanidins of Zijuan had better inhibitory activity than acarbose and EGCG.This study showed that Zijuan proanthocyandins had become anti-diabetic drugs and weight-loss potential.