Abstract: According to the conventional water quality survey data of the waters of the northwest Liaodong Bay in September 2013 and May 2014, the pollution condition, main pollutants and their source of northwest of Liaodong Bay waters were studied.The results showed:the pollution distribution characteristics of the waters of the northwest Liaodong Bay present offshore decreasing.The area pollution belongs to land-source pollution.The controlling of land pollutants discharge will effectively control the waters pollution.The spring organic pollution indexes of frist kind and second kind were more than 1, some stations organic pollution indexes of third kind were more than 1, the spring have heavier organic pollution degree than autumn, the pollution indexes and the distance from the coast were negative correlation and with a more regular offshore distribution characteristics.The eutrophication indexes of all marine functional areas in this area are more than 1, which are a trend of slight eutrophication.The eutrophication characteristicpollutant of the waters was the inorganic nitrogen, and the organic characteristic pollutant was COD.