Salt pan ecosystem of Tuticorin was studied for the distribution of Phytoplankton in two condenser ponds in a particular station, where artemia population was very high. This was monitored for one year in two ponds. Physico chemical parameters were also studied. The population of Bacillariophyceae dominated during monsoon season. Chlorophyceae was high during summer. Phytoplankton density was correlated with artemia population. Artemia biomass was at a maximum during monsoon when the species The occurrence of Rodophyceae was noted in premonsoon season, while Erythrophyceae was recorded in summer.