Background: Marine algae are shown to contain a wide range of bioactive compounds, which have commercial application in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. The biological activity of the natural bio-active compounds in algae has wide effects on bacteria, tumors and antioxidant activities. The purpose of this study was to determine antioxidant and antibacterial activity of the marine algae. Materials and Methods: The ethanol extracts of three species of green, brown and red algae were done by soaking method from northern coast of the Persian Gulf in Busheher province. Antibacterial activity of L. monocytogenes and E. Coli were performed using disk diffusion and well method, and also antioxidant activities of ethanol extracts of added three species accomplished using DPPH, FRAP and PMB tests. Results: The highest antioxidant activity was belonged to brown algae C. trinodis. Meanwhile Algae extraction was not revealed antibacterial activity against E. coli, but showed antibacterial activity against L. monocytogenes. Conclusion: In this study algae species was exhibited excellent antioxidant activity when compared with their antibacterial effects. The highest anti-oxidant activitie was found in brown algae C. trinodis.