Hydrological investigation data were used to analyze the characteristics of the salinity distribution and the extenion of the Yellow River Diluted Water (YDRW) in the sea. After the Yellow River relocatid eastward to Laizhou Bay in 1976,it was found that the YDRW extends east ward and northeast ward during the plentiful water period (from June to October), and southeast ward during the dry season (from November to May). The main factors affecting the extension direction of the YRDW were found to be theYellow River runoff, monsoon and current systems near the Yellow River Estuary. The critical value of discharge which makes the YRDW turn eastward or northeastward is 2.2×109m3 per month.