Abstract: Objective:To study the effects of ⁶⁰Co-γ ray irradiation on the antioxidant and whitening of Rhodiola rosea ehanol extract. Methods:Rhodiola rosea was treated with different doses(5,10,20,30 kGy)of ⁶⁰Co-γ ray,using 1,1-Diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging rate,2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid(ABTS)free radical scavenging rate and ferric reducing antioxidant power(FRAP),tyrosinase inhibition experiment,mouse B16 melanoma cells experiment,to evaluate the antioxidant and whitening effects of Rhodiola rosea extract after irradiation. Results:Compared with the non-irradiated group,the antioxidant activities and whitening activities of Rhodiola rosea extract in irradiation groups were increased. Among them,the Rhodiola rosea extract in the 20 kGy irradiated group had the best effect,and the IC₅₀ value of DPPH free radical scavenging was 3.75 μg/mL,the IC₅₀value of ABTS free radical scavenging was 44.88 μg/mL,the FRAP value of ferric reducing antioxidant power was(1.90±0.05) mmol/mg,the IC₅₀ value of tyrosinase inhibition was 244.10 μg/mL. Rhodiola rosea extract could effectively reduce the synthesis of melanin in mouse melanoma cells,and had no cytotoxicity when the concentration was less than 0.50%. Conclusion:The ethanol extract of Rhodiola rosea by 20 kGy ⁶⁰Co-γ ray irradiation had the strongest antioxidant activity and good whitening effect.