This research aimed to study the phytochemicals and antioxidant activity of the Seablite (Suaeda maritima). The Seablite (Suaeda maritima) from Hat Chao Samran Subdistrict, Muang District, Phetchaburi Province. The ethanol extracts of Seablite were prepared by maceration. All of the extracts were evaluated for their phytochemical include terpenoids, flavonoids, alkaloid, cardiac glycoside, saponins and tannin. Total phenolic contents were investigated using Folin-Ciocalteu method. The antioxidant ability of the Seablite extracts were using DPPH assay. It was found that amount of Total phenolic compound of seablite fresh leaves bright green extracted was a maximum amount of 328.62 ± 0.01 mg GAE/g. The analysis of antioxidant activity by DPPH found that seablite scalded green leaves have the highest antioxidant activity of 44.91 ± 0.02 which corresponded to the phytochemicals found. The tannins and flavonoids were compounds that often exhibits antioxidant activity.