To investigate the biological activities of anthocyanins, which are induced by cadmium in A. imbricata, the antioxidant properties of anthocyanins were investigated using various antioxidant assays, namely 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azinobis-(3-ethylbenzthiazoline-6- sulfonic acid) (ABTS) radical scavenging activity, reducing power, and β-carotene bleaching assay. Results showed that anthocyanins exhibited excellent antioxidant activities in all assays and the EC₅₀ values of DPPH radicals scavenging, ABTS radicals scavenging, reducing power and β-carotene bleaching assay were 19.08, 10.69, 40.93, and 44.19 μg·mL^-1, respectively. The Cd2+ chelation potency of anthocyanins was also investigated in vitro. Under given conditions, Cd²⁺ chelating ability of anthocyanins increased significantly with increase in contact time, anthocyanins concentration in dialysis tubing and Cd²⁺ concentration in solution. Based on these results, anthocyanins inducibly synthesized by Cd²⁺ treatment was a powerful antioxidant, as well as Cd²⁺ chelator, might play a role in detoxification of Cd in A. imbricata.