Abstract : The crude hydroethanolic extract of Ferula sulcate Dell, was prepared by Solid-Liquid Extraction (S.L.E); and its fractionation was carried out by Liquid-Liquid Extraction (LLE).The yield of the various extracts obtained are in the following decreasing order: AcOEt˃ n-BuOH˃ MeOH70%˃ EHx˃ EAq. Quantitative estimation of total flavonoids and polyphenols by the spectrophotometric method showed that the extracts AcOEt, MeOH70% and n-BuOH have the highest content of phenolic compounds. The aqueous extract gave the lowest content with 41.20± 2.0 mg EAG/g MS.. HPLC analysis of the ethyl acetate extract allowed us to suspect the possible presence of five phenolic compounds: Chlorogenic acid 20.18%; Vanilic acid 0.25%; p-coumaric acid 1.66%; Rutin 58.02% and Quercetin 6.74%. The AcOEt ethyl acetate extract has a strong anti-radicular activity with an IC50 equal to 0.23 ± 0.01mg/ml. The comparison of the anti-free radical activity of n-butanol n-BuOH extract with that of VitC shows a significant difference (P˂ 0.05) with an IC50 value of 0.40 ± 0.03 mg/ml. The AcOEt extract expresses a scavenging effect of ABTS radicals with an IC50 of 0.16 ± 0.006 mg/ml. The IC50 value of the extract remains significantly different from BHT and Quercetin.