Abstract: River plays an important role in the transport process of terrigenous matter from land to sea.In recent years, the water and sediment flux of the Yellow River into the sea has changed drastically under the influences of both natural and ceaselessly strengthened human factors, which severely impacted the ecological environment of the estuary and offshore.Seawater environment of the Yellow River Estuary before, during and after the water and sediment discharge regulation (WSDR) project period was studied in 2013.The studies involved the content, distribution characteristics and nutrition structure of the main water quality factors, and then the comprehensive and correlation analysis were done.The results showed that the water environmental state of the Yellow River Estuary changed obviously in the influence of the WSDR project.The salinity and chlorophyll a concentration reduced significantly during the WSDR project, and enhanced slightly after the project.The concentrations of nutrients and chemical oxygen demand (COD) were highest during the WSDR project, followed by that after and before the project.The results of plane distribution analysis showed that the dense contours of the salinity, nutrients, COD and petroleum content were at the entrance of the Yellow River Estuary, and the contours extended to the sea in the tongue shape as the WSDR project progresses.The WSDR project exacerbated the eutrophication and organic pollution in the survey sea area, but at the same time, relieved the unbalance in nutrients structure to some extent.And the results of correlation analysis provided a further sign that the WSDR project was a major control factor for the distribution and change of the main water quality factors in the survey sea area.Moreover, the WSDR project made the leading role of human factors more significant in the material flux from the Yellow River to sea.