Objectives: In order to study the antioxidant activity of essential oil fractionated parts from the Citri reticulatae Pericarpium (CRP) of Citrus kinokuni Tanaka collected in different time and five representative compounds from the peel of C. reticulata Blanco. Methodology: Firstly, essential oil (EO) were obtained from C. kinokuni Tanaka. The EO were treated with vaccum fractionation method while the different separated parts were analysed by shimadzu Gas chromatography-Mass spectrometer(GC-MS) along with the five characteristic compounds were tested for the antioxidant activity by using antioxidant activity techniques such as, ABTS (2,2’ azino-bis (3-ethylbenzthiozoline-6)-sulphonic acid) and FRAP (ferric reducing/antioxidant power), respectively. Results: According to FRAP method, the total antioxidant activity of EO obtained at 100°C is 3.19 at 0.15 mM concentration, which is comparatively more than other fractions of EO. While the antioxidant activity of EO obtained at 110°C and 160°C is 2.377 and 2.189 at 0.3 mM concentration, respectively while at 0.15 mM concentration, the antioxidant activity is 1.627 and 1.005, respectively. The antioxidant activities of Limonene and Decanal is 2.095 and 2.019 at a concentration 0.3 mM, which are more than its other representative compounds. In ABTS method, the standard curve is not perfect, resulting the effect on the antioxidant activity of each sample. Antioxidant activity of EO at 240°C is 0.072 at 0.3 mM concentration while the rest of others EO samples and even 05 representative components, the antioxidant activities are below zero. Conclusion: EO separated parts obtained from the CRP of C. kinokuni Tanaka and five representative compounds exist antioxidant activity upto certain extent.