Abstract: The distribut on of salinity on the surface in the Gulf of Pechili during the summer year is entirely controlled by the discharge of rivers in its surroundings, and the discharge of rivers is in turn depend upon the rainfall on the ecntirent in the same season. Among different rivers flowing in to the gulf the Yellow River exhibits the most conspicuous influence upon the distribut on of salinity on the surface water, therefore the isohalines more or less take the shape to surround the outlet of the Yellow River (ChartⅡ-Ⅵ).