Hypnea musciformis belonging to family Rhodophyceae Genus name is Hypnea. To the best of our knowledge the algae Hypnea musciformis was evaluated for Phytochemical study Such as Physico-chemical analysis, elemental study, metal analysis. The different extracts undergo Preliminary Phytochemical analysis for the identification of various Phytoconstituents. It answers positively alkaloid, carbohydrate, glycosides, tannins, protein, amino acid and steroid ...Pharmacological activity was screened by which methanol extract showed the maximum inhibition of arthritis. Then Methanolic extract was subjected to column chromatography to isolate the compound and identified by TLC and confirmed as Flavonoid by spectral studies as Astaxanthin and Hesperidin. Which responsible for reduction of arthritic activity and Free radical like Nitric oxide and DPPH. In Histopathological studies Methanolic extract of Hypnea musciformis shows effective in curing the synovial damage as compared to arthritic control. Our result showed that the methanol extracts and isolated compound possess significant anti-rheumatoid activity. It may due to the presence of Phenolic and Carotenoids terpene constituents. From the above results it can be concluded that Hypnea musciformis can be used in the treatment of anti-rheumatoid arthritic disease as a novel drug on the basis of clinical trials. Chemistry of marine natural products is a newer area of potential resources for discovering new therapeutic tangents developing new leads.