During 1989~1990,36 species,under 22 genus of phytoplankton were indentified in total in the waters neat four islands.With 31 of Bacillariophyta,7 of pyrrophta.During 1996~1998,53 species,under 36 genus were indentified in total in shore,with 44 of Bacillariophyta,11 of Pyrrophyta and 1 of Cyanophyta.The community similarity coefficient of the phytoplanton was compared between in shore and the waters near four islands.