Ulva lactuca, common seaweed abundantly found along the coasts of Raigad district of Konkan region of Maharashtra. Phytochemical screening of the extracts was carried out as per the standard procedure, using water, HCL (1%), ethanol, ethyl acetate, methanol, chloroform, benzene and petroleum ether. The different extracts of Ulva lactuca showed the presence of flavonoids, glycosides, phenolic compounds, saponins, steroids, tannin etc. The alga was extracted using Four different methods were used to evaluate the antioxidant activity of the extracts, including DPPH radical scavenging assay (1, 1-diphenyl-2-picryl hydrazyl), FRAP, Reducing power and Total phenolic contents. The results obtained suggest that Ulva lactuca is used as a best source of food and fodder, but has less important as a source of antioxidant.