The analyses of data, obtained in comprehensive surveys on the fisheries ecology and oceanography in the Changjiang River estuary May, 1999 indicated that the ichthyoplankton community structure and its spatiotemporal dynamics could be related to the construction of the Three-Gorge Dam in the upstream and the recruitment mechanism of commercial fisheries in the waters. It was showed that hydro-physical conditions in the Changjiang River Estuary are complicated with great variation in salinity and transparency. Under this variable environment, sixteen families and 20 species of ichthyoplankton were recorded with 6644 eggs and 14932 larvae in the samples. In both the vertical and surface sampling, the number of Engraulis japonicus was dominated, comprising 95.53% in the vertical water body, and 90.80% in the surface; the second was Chaeturichthys hexanema; and the third was Chaeturichthys hexanema and Hemisalanx prognathus Liza haematocheila. was the second and third in vertical waterbody; and in the surface water body, the second and third were Chaeturichthys hexanema and Coilia mystus. With regard to the index of relative importance (IRI), Engraulis japonicus was absolutely dominant component; Chaeturichthys hexanema were dominant components, with IRI of more than 100 4 regular components with IRI of 10-100 were Coilia mystus, Hemisalanx prognathus, Liza haematocheila and Pseudosciaena polyactis. Surface temperature significantly affected egg survival and occurrence in horizontal samples; the obviously close relation of zooplankton biomass to larvae development in the vertical samples could indicate the direct impact from the hydroelectric facility in the upstream Changjiang River on the developmental environment in the ecosystem.