Bung Binh Thien is considered a natural wetland conservation area in the Mekong Delta, Vietnam with a diverse flora and fauna ecosystem. The survey on phytoplankton composition here was conducted in the dry season of 2019. The results obtained 140 phytoplankton species belonging to 5 algae phylums. Of which, 54 species belong to Chlorophyta, 37 species of Bacillariophyta, Cyanophyta and Euglenophyta, respectively, have 27 and 20 species, and lastly, Dinophyta has 2 species.