In this study, in order to search for new functional materials from natural products, was carried out the study of antioxidant active ingredients in persimmon calyx(calyx of Diospyros kaki Thunberg). I have experimented with the effect of antioxidant activity of five different extract(MeOH, n-hexane, EtOAc, n-BuOH and $H_2O$ extract) obtained from persimmon calyx. As a result, the butanol extract, that is the main component fraction of antioxidant activity was found. Three compounds were isolated by silica gel column chromatography from the n-BuOH extract of persimmon calyx. Their structures of compound 1, 2 and 3 isolated from n-BuOH extract of persimmon calyx were identified as quercetin, (+)-catechin and gallic acid by using the TLC, $^1H$-NMR and $^{13}C$-NMR.