Our present study include the species diversity of phytoplankton of a semi-lentic water body within the khari of Golapbag campus, the university of Burdwan and its relation with physico-chemical parameters of the water body to establish the occurrence of the various phytoplankton throughout the year. Species diversity index value 3.824, 3.701 and 3.354 in pre-monsoon, monsoon and post-monsoon respectively indicates the quality of the water body. Chlorophycean representatives are dominant mostly and Cyanophycean members are least in representation. Plankton density reaches its maximum level in monsoon time. This work demonstrates changes in phytoplankton diversity and expresses the possibilities of using these minute organisms as an indicator in biomonitoring system to determine the quality of water body.