Abstract: The optimal conditions of proanthocyanidins extracted from seabuckthorn( Hippophae rhamnoides L.)seed residues were obtained by orthogonal test,on the basis of one factor tests. The optimal condition of ethanol extraction was ethanol concentration 80%,temperature 35 ℃,liquid to solid ratio 8 ∶ 1 m L / g,extraction time 1.5 h,p H3.0.Under this condition,proanthocyanidins was 97.31 ± 0.48 mg / g seabuckthorn( Hippophae rhamnoides L.)seed residues. Antioxidant activities were tested,using crude extract lyophilized power. Antioxidant activities of proanthocyanidins extracted from seabuckthorn( Hippophae rhamnoides L.) seed residues were investigated with the method of scavenging hydroxyl and DPPH. IC_50 was calculated. Results indicated that the proanthocyanidin extracts had higher antioxidant activity than vitamin C on the scavenging ability of DPPH.The ability on scavenging hydroxyl was low.Methods MTT assay was employed to determine the cell viability of proanthocyanidin extracts in B16 cells.The IC_50 was 542.78,199.25 and 82.58 μg / m L when B16 cells was exposed for 24,48,and 72 h,respectively.It was suggested that the B16 cell viability followed the dose-and time-dependent manner.