I n this paper , the rela tionship between plankton in the eel ponds and eel feeding was described , and the dominant plankton species of “good water quali ty” sui table for eel-culture , the ecological characterist ics in the eel ponds and in the t radict ional cultur ed-fishes ponds were expounded .The me thod for cont rolling water quali ty in the eel ponds was also discussed .The resul t of the pr esent research indicated that plankton communit ies in the eel ponds was significantly differ ent from tha t in the tr adict ional cul turedfishes ponds .The dominant species of phytoplankton in the elve r ponds was Chloraphyta , its biomass accounted f or over 80 % of total phytoplankton biomass ;and the dominant species of phytoplankton in the grow-out eel ponds wer e Bacil lar iophyta and Chloraphyta , both of the above accounted for 40 % and 37 % of total phytoplankton biomass respectively .The dominant species of zooplankton in the eel ponds wer e Ro ti fer a and Copedode , the per centage of Cladocera was lower .The plankton' s abundance and str ucture af fected eel feeding significant ly .