Abstract: The present report deals with the zooplankton of the foodstuff collected along theTaichu-Yang and Dajie-Yang of the Chu-San region duritig 1960-1961. The results are asfollows: The average total biomase of zooplankton is 88 mg/m³ in this region, and the higbestis 140 mg/m³ in July and the lowest is 4 mg/m³ in February. In general, it reaches a maximum in summer and a minimum in winter. Its seasonal va-riation is just the same as the water temperature. There are 100-250 mg/m³ of the total biomass of zooplankton distributed in the southeastof the fishing ground and 250-500mg/m³ distributed outside of it. The dominant zooplanktons are the eurythermic low-saline neritic species and the brackishwater estuarine species. They are the Labidocera cuchacta, L. bipinnata, Contropages dorsispin-atus, Tortanus vermiculus, Schmackeria poplesia, Gastrosacous ko jimacnsis, Acctes ohinensis,etc., and are mainly distributed in the west of the fishing ground and Hangchow-Bay. Thereare also high-saline oceanic species, including Calanus parper, Undinula vulgaris, Eucalanuscrassus, Euchact plana, Sagitta bedoti, S. enflata, etc. They are mainly distributed in thesouth and southeast of the fishing ground.