Icthyoplankton composition, distribution and dominance in the Oujiang estuary （Zhejiang Province） were investigated June-September of 2007. Eggs and larvae of 18 species representing of 6 orders and 11 families were identified and counted. Clupeiformes and Mugiliformes orders had the most species. In June, most abundant larvae were Gobiidae sp. and Johnius belengerii which together made up 91.33% of total larvae. These dominant larvae were resident species and the diet for some economical fish. Yet in September, Pennhia argentatus and Gobiidae sp. were the most abundant larvae which contributed to 69.56% of the total larvae. Pennhia argentatus was important economical species in the studied area. The major spawning ground located in the waters off the Damen Island in June, the main spawning period. However, in September the spawning ground mainly located in the east waters of the Dongtou Islands. The runoff from Oujiang, the latitude, the background of topography and geomorphy, the hydgological features and its nutrients of waters from numerous islands, narrow water channels, dense reefs and the cross of fresh water and marine water are all responsible for the ideal spawning and nursery ground near the Oujiang estuary.