Antioxidant properties of eight Paeonia suffruticosa (Ps) extracts (Ps-1 to Ps-8) were evaluated. The respective half maximally effective concentration (EC(50)) values of Ps-1 ~ 8 were 10.0, 9.8, 63.6, >100, 3.8, 85.1, 6.9, and 0.7 μg/ml for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) radical scavenging efficiency and 22.9, 11.4, 53.1, >100, 7.5, 97.6, 43.7, 4.2 μg/ml for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS·(+)) radical scavenging capacity. The Ps-8 exhibited high free radical scavenging capacity, ion-chelating ability, reducing power, and inhibition of lipid peroxidation, which may have been attributable to its abundant phenolic and flavonoid content. In Hs68 and B16 cells treated with 100 μg/ml Ps-1, Ps-3, Ps-4 and Ps-6, expressions of toxic activities were lower than those in cells treated with arbutin and ascorbic acid. The antimelanogenesis properties were also tested in B16 cells. Extract Ps-1, and particularly extract Ps-6, considerably inhibited cellular tyrosinase and 3,4-dihydroxyphenylalanine (DOPA) oxidase activity and also reduced melanin content in B16 cells by down-expression of melanocortin-1 receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related proteins-1 (TRP-1). The results suggest that P. suffruticosa extracts have antioxidant and antimelanogenesis activities with potential applications in cosmetic materials or food additives.