Abstract: This study aimed to develop the enzymatic preparation of ABTS•+ radical cation using laccase from Trametes versicolor. The result revealed that ABTS•+ preparation with the aid of the enzyme was reasonable easy, quick and high yield. The radical yields were controlled by concentration of ABTS substrate and enzyme amount. These ABTS•+ radicals were used for antioxidant activity assay of 31 Thai vegetables. The dried sample powders extracted by ethyl alcohol showed as high TEAC values as in Spondias pinnata, Eugenia grata and Polygonum odoratum. TEAC values determined using ABTS•+ and DPPH• radical decolourisation methods were strongly consistency and correlate with total phenolic content in the samples. The quick and easy of the method as well as stability of the radical and reliable of the antioxidant capacity including environmental friendly suggest it to be a potential method for a total antioxidant activity measurement in biological samples.