ABSTRACT Phytoplankton are the subject of great interest becomes of their role as primary producers in an aquatic ecosystem. The quantitative and qualitative studies of phytoplankton may provide good indices of water quality and capacity of water to sustain heterotrophic communities. The phytoplanktonic community are 29 species of the following 4 group Chlorophyceae 12 Species (48.00%), Myxophyceae 9 Species (36.00%) Bacillariophycveae 3 Species (12.00%) and Euglenophyceae 1 species (4.00%) has been observed Khairkatta Dam during study periods. The Diversity of the different phytoplankton in more summer season than during winter and rainy season. REFERENCES Adesau, T.A and D.I Nwankwo, (2008). Effect of water quality idices on phytoplankton of a sluggish Tied Creec in Logs, Nigeria. Pakistan J. Biols.Sci., 11, 836-844. Adoni A.D.G., Joshi, K. Gosh, S.K. Chourasia, A.k. vaishya , Manoj Yadav and H.G Verma (1966). Work book on limnology. Pratibha Publisher, Sagar. Pp. 1-166. Ahmad M.S. (1996). Ecoigica survey of some agal flora of polluted habitat of Darbhanga. J.Environ pollut., 3. 147-151. Ahmad M.S. and E.N Siddique (1995). Freshwater diatom of Darbhanga. J.Freshwater Bios., 7, 41-48. Bhatnaga G.P (1988) seasonalchanges of phytoplankton in relation to some physic chemical factor in lower lake. Bhopal,Geobios 15:170. Chaturvedi R.K., K.P.Sharma, Kamaayani Sharma, S.M Bharawaj and S.Sharma (1999). Plankton community of pouted water around Sanganer, Jaipur. J.Environ. Pout., 61 77-84. Cheappa N.T., J.M Borba and O. Rocha (2008). Phytoplankton community and physical-chemica characteristics of water in the pubic reservoir of Cruzeta, RN, Brazil. Braz. J.Bios., 68, 477-494 Kamat,s. and V.Sima (2000). Hydrological studies of two temple pond in ponda aluka Goa. Ecol. Environ. Con., 361-362. Sultana L.H. and Gupta S (2009). Phytoplankton diversity and dynamics of Chatla floodplain lake Barak Valley, Assam, North East India- A seasonal study. J. Environ. Bios., 30, 1007-1012 Narayan, R,K.k Saxena and S. Chauhan (2007). Limnolologica investigation of Texi Temple pond in district Etawah ( U.P). J. Environ. Biol., 28, 155-157. Pundhir, P. and K.S. Rana (2002). Population dynamics of phytoplankton in the wetland area of keoladeo National Park, Bharatpur, (Rajasthan). Ecol. Environ. Conser., 8, 253-255. Philipose M.T (1960) Fresh water phytoplankton of Inland Fisheries Proc. Symp. Algol Icar, New Delhi 272-291.2. Shekhar et. al. (2008). Studied phytoplankton as indicator of water quality with references To industrial pollution. Zafar AR (1964). On the ecology of algae in certain fish pond of HyderaIndia. Distribution of unicellular and colonial form. Hydrobiology. 24: 556-566.