Branchyuran crabs are the most diverse groups of crustaceans. They are found in most marine habitats such as coral reef, sandy beach, rocky beach, mangroves and seagrass meadows. In this study, we investigated the species composition of branchyuran crabs from ten sampling locations belonging to three habitats (mangrove forest, artificial dykes, sandy beaches) at Duyen Hai town on August (rainy season) and December (dry season) of 2017. Our result supported that, there were 22 species belonging to 10 genera of 6 families presented in the research area. The Ocypodidae family is the most abandon with 45.5% species, following are Grapsidae (22.7%), Sesarmidae (13.6%), Portunidae (9.1%), Matutidae (4.5%) and Xanthidae (4.5%) respectively. Densities of branchyura crabs ranged from 2.0±1.1 (inds/m ) to 17.2±4.3 (inds/m ), the Mangrove forest habitat more diversity in species than Sandy beach and Artificial dykes habitat. In analysis following season, the rainy support for more diversity than dry season.