The aquatic environment and zoobenthos fauna are closely related in a water body. In recent years, the use of zoobenthos to assess the quality of surface water environment is of interest because this method causes less environmental pollution and is less costly. The study was conducted to evaluate the distribution of zoobenthos fauna in the Bac Vam Nao flood control area, An Giang. Three samples of benthos (VN1-VN3) were collected in two periods, the first in March and the second in September 2020. The results have found eight species belonging to three phyla of Mollusca, Annelida and Arthropoda. In which, Mollusca phylum had the highest number of species with six species (70%) and the lowest was Annelida and Arthropoda with one species each (12.5%). In the dry season, Macrobrachium sp. (Arthropoda) dominated at all three sampling positions. In the rainy season, Mollusca is dominant with Pomacea canaliculate, Gyraulus sp., Filopaludina (F.), Sumatrensis speciosa species. Density of zoobenthos at three monitoring locations in the Bac Vam Nao flood control area ranged from 170 to 290 individuals/m² in March and from 40 to 70 individuals/m² in September, reaching the highest value is at the end of Than Nong canal adjacent to Cai Tac canal (VN3) in March and the lowest at the middle point of Than Nong canal adjacent to K26 canal (VN2) in September. The diversity index H' of zoobenthos at three locations in the Bac Vam Nao flood control area through two monitoring periods in 2020 ranged from 0.36 to 2.24, classifying water quality from mild to very polluted. The diversity of zoobenthos at the monitoring sites is subjected to seasonal change in which the H' index in the dry season is lower than that in the rainy season. The current findings showed that the zoobenthos composition reflected the bottom water quality of the study area. More studies are needed to increase the accuracy of this assessment method.