Biodiversity is measured at different leves of Biological set up together with genes, species, and ecosystems along with their interactions. The aim of Convention on Biological Diversity (CBD) are sustainable use of its components and fair and equitable shå of the benefits from the use of genetic resources. Flora is essential for sustaining all animal life of an area and also for maintaining heritable environment for that area. Adequate knowledge of flora is necessary for planning sustainable development of that area. Pulicat Lake is the second largest brackish water lagoon after Chilika Lake of Orissa along the east coast of India. Estuaries and lagoons have brackish water which shows high biological productivity than fresh or sea water. Hence it has wide range of aquatic, terrestrial flora and fauna. The World Wide Fund for Nature declared it as a protected area. Present study aims to explore the floristic composition and its conservation methods of Pulicat Lake. Flora of a particular region depicts its ecological, hydrological, topographical, historical identification. The regional/ landscape diversity of pulicat lake includes mangroves, sand dunes and beaches, scrub jungle, wetlands with herbs and shrubs and cultivated fields with cashew, paddy, fruits and vegetables. It also attracts and supports many migratory and resident water birds. Hornell (1924) makes a passing remark about the catfish Arjus jella (Thoppa keluthi) in the lake, as common on the submerged vegetation of Halophila. Chakco et al., (1953) have recorded 59 species of phytoplanktors and 23 species of zooplanktors, but Krishnan and Sampath (1973) have recorded much less, only 16 phytoplanktors, but more zooplanktors, 35 species. Today, it is still less, about 7–10 species of Zooplanktors alone, in the polluted southern region of the lake, but about 20 species, elsewherec. Chacko et al. (1965) have given an exhaustive list of the flora in the varius habitats of the Pulicat Lake. Radhakrishnan (1971 and 1977) observed that the most weedy areas of the lake have the bottom vegetation of Halophila ovalis and the eelgrass Enahalus Koenji, but in the southernmost region there is the sea grass Diplanthera univerves, along with Halophila ovalis and the brown algae spp. Rosenvingia intricate and green algae like Enteromorpha and Chaetomorpha spp., Gracilaria verrucosa, Oscillatoria spp, Acetabularia calyculus, Quoy and Gaimard, foming the bulk of the weed–bed (Thangavelu and Sanjeeva Raj,1988). Aquatic macroflora of this lake are described by Chacko et.al. (1953). Macrophytes like Halophila ovails popularly called sea grass and syringodium isoetifolium are more common in the central zone, around the Kuuvithittu mudflat. Calamus rotang and Cappris rotundifolia are endemic to this area only. Pulicat Lake is wonderful wet land which shows wide diversity in both flora and fauna.