Abstract: The estimations of primary production of phytoplankton in the pondin Sanjiang Plain were carried out in 1987 with white-black bottle method.The correlation between primary production and the major ecologicalfactors are also discussed. On sunny days, the water layer with the maximum production is atthe depth of 50% transparency, where the light intensity is about 200001x. The compensation depth changes with the climate. The correlation between primary production and biomass, Mg²⁺ is positive linear dependence. The P/B coefficient of phytoplankton under aunit of water surface is 177.7 during growth seasons. The rate of utiliza-tion of total radiation by phytoplankton is 0.31%. Nitrogen ip the wateris the Limiting factor for primary production of the pond.