The aims of our study were the quantification of proanthocyanidins using colorimetric assay and the determination of antioxidant ability by DPPH radical scavenging activity. Inhibitory effects of the methanolic extracts from jujube on two enzymes, that is, α-glucosidase and a-amylase, were also investigated regarding their potential anti-diabetic activities. The scavenging effects of jujube extracts increased positively with the proanthocyanidins concentration between 0 and 4.5 μg/mL and the DPPH radical scavenging rate of jujube proanthocyanidins extracts at 4.5μg/mL was as high as 96.6%. The inhibitory activities of proanthocyanidins extracts (112.5 μg/mL) from jujube against the α-glucosidase could reach about 93.8%, and that against the a-amylase was 91.34%, which indicated that the proanthocyanidins extracts possessed strong antidiabetic activities. Our study, for the first time, revealed the anti-diabetic potential of jujube and this study could be helpful to develop medicinal preparations or nutraceutical and functional foods for diabetes and related symptoms.