Tha analyses of the data collected in recent years, together with the invdstigation results from some fisheries research organisations in the past,have shown that the fluctuations of the annual runoff of Changjiang River mostly and directly affect on the temperature, salinity and the distribution of the diluted water in the Changjiang Estuary and its ad jacent sea areas.The outstanding correlations between Changjiang River runoff and the magnitude areas And their distributions of zooplankton bionzass in the coastal waters, the positrons of the commercially important fishing grounds, and the catches of same important commercial fishes have been found also. Some historical facts in the fisheries of hairtail, Ohub mackerel and scads in tha ChangJiang Estuary, Zhoushan anal Yushan Tishing Grounds are to be used to illustrate the phenomena mentioned above.