Seaweeds (Marine macroalgae) area large group of marine organisms containing important phytochemical constituents with various biologicalactivities .They are potentially prolific sources of highly bioactivese condary metabolites, which manifest many of the rapeutic effects like anti-cancer, anti-oxidant, anti-inflammatory and anti-diabetic activities. Seaweeds are used by many Asian cultures fortraditional medicine preparations. The Caulerpapeltata was collected from Rameshwaram coastal area it was shadedried, madein to powder using standardized procedure to get Caulerpapeltata Methanolic Extract (CPME). The phytochemicals and Gas Chromatography-Mass Spectrometry (GC-MS) analysis was done on prepared CPME for identifying the bioactive compounds Phytochemical in vestigation suggests that the Caulerpapeltata exhibited the presence of phytochemicals like Alkaloids, Carbohydrates, Phytosterols, Saponins and Diterpenes,which may contribute to its biological activities. GC-MS analysis showed 28 variety of compounds,among which Dibutylphthalate, n-hexadecanoic acid, and1,2–Benzenedic arboxylic acid was found in high percentage. The phytochemical studies and the compounds available in GC–MS showed that the Caulerpapeltata contain important bio active compounds,which may have anti-microbial,anti-fungal and anti-canceractivity. Further research is needed for finding its use in development of new pharmaceutical agent and its safe consumption by human for various health benefits.