The study on the species composition of Perciformes in Hau river basin in Can Tho City, Vietnam, was conducted from August 2009 to May 2010 with a total sample of 432. These samples were collected in 7 sites in the dry and rainy seasons and lentic and lotic water systems by different methods and equipment. The samples were analysed and identified by morphologic characteristics (7 measured indexes and 9 counted indexes). The taxonomy of these species were ordered by Fishbase taxonomic classification. The study found that there are 43 species belonging to 14 families (Ambassidae, Anabantidae, Channidae, Cichlidae, Coiidae, Eleotridae, Gobiidae, Helostomatidae, Nandidae, Osphronemidae, Polynemidae, Scatophagidae, Sciaenidae and Toxotidae) and 31 genera. Among these species, Datnioides polota (Hamilton, 1822) and Toxotes chatareus (Hamilton, 1822) are indexed in Vietnam's Red Data Book (2007). Moreover, 9 commercial species, 17 estuarine species and 3 exotic species were found and complemented 8 species for the study area. The result of study is believed to be essential and pivotal to the management and use of the bio-diversity of this order of fish.