The aim of this study was to identify and quantify the phenolic compounds of the Ethyl acetate extract from Lepidium draba using HPLC-TOF/MS; and to investigate the antioxidant potencies. In this work, we have found that the Ethyl acetate soluble fraction of L. draba is a good source of antioxidant, which is the result of its phenolic acids and flavonoids. Five methods were conducted, to determine the antioxidant components of the Ethyl acetate extract: DPPH, ABTS, CUPRAC, Reducing power assay and Metal chelating assay. Nineteen compounds from which 13 phenolic acids and 6 flavonoids known for their pharmacological properties were identified by using HPLC-TOF/MS technique: Gallic acid, Gentisic acid, Chlorogenic acid, 4-Hydroxy benzoic acid, Protocatechuic acid, Caffeic acid, Vanillic acid, 4-hydroxybenzaldehyde, p-coumaric acid, Chicoric acid, Ferulic acid, Rosmarinic acid, Salicylic acid, Catechin, Rutin, Hesperidin, Apigenin-7-glucoside, Quercetin, and Kaempferol. All These compounds were identified and quantified in Lepidium draba for the first time. The IC 50 and A 0.50 of the Ethyl acetate extract were 305.69±1.22, 39.42±0.45, 152.27±0.38 and 183.83±2.47 μg/mL in DPPH, ABTS, Metal chelating assay, and CUPRAC. However, the results indicate that L. draba is a good source of natural antioxidants.