The main purpose is to investigate the phytoplankton communities in the shallow oxbow lake and study the composition of the species in different sampling points along the oxbow lake. Making comparison between the phytoplankton communities in seven specific sections along the oxbow lake. And comparing between the phytoplankton communities along (left, middle, and right) sides of the oxbow lake. Finally, monitoring the physical-chemical parameters along the seven sections and make comparison between the seven sections.......conclusion, the oxbow (Nagy-morotva) was extremely heterogenic lake, during the laboratory work has been identified many different phytoplankton communities in the seven sections and the sides along the oxbow lake. The identification showed that there was many kinds of species dominated in the first five sections and decreased to very few dominated species (eg.Cryptophyta phylum has highest abundancy) at the last two sections. And also the same in the (Right, Middle, and Left sides), except the Middle side showed that the highest abundance of (eg.Cryptophyta phylum) started from the fifth section till the end of the lake.