Abstract: The population and biomass of algae were studied in embanked fish pond ecosystem along the coastal area of Jiangsu province. Seven phylum and 127 species of algae were found in the fish-pond. The average amount and biomass of algae were 143.92?06units/L and 105.6 mg/L during 7 months(from April to October). The change in composition, amount and biomass of algae was dynamic. Cyanophyta, Chlorophyta and Bacillariophyta were dominant phylum of algae in the ecosystem. The quantity and biomass of Chlorophyta and Bacillariophyta were larger than those of Cynaophyta in Spring, but smaller in Summer. The average biomass of three dominant phylum was similar in Autumn. The ecosystem of embanked fish pond in the coast area could therefore be classified into medium production level. The high salt content and low fertility in the coastal saline soil were overcome in the ecosystem. It is shown coastal land resources could be fully used for aquaculture to achieve production level similar to those obtained from high fertility soil.