Abstract:This paper study eutrophication of water quality indexes, such as dissolved inorganic nitrogen (DIN), phosphate (DIP) and chemical oxygen demand (COD) in Zhongjieshan mariculture zone in 2010. The results show that in spring, summer, autumn, the sea surface water temperature, salinity, pH, dissolved oxygen in the monthly average values were significantly seasonal differences. The average monthly values (including COD, DIN, and DIP) showed also significant seasonal difference. The mean value of COD was relatively low, which was lower than the first class seawater standard. And DIN in most stations was inferior to four categories of seawater, and the performance of the DIP for most stations belonging to the two or three kinds of sea water. A value of E indicated that the sea water at high eutrophication, eutrophication index and the dominance of COD, followed by DIN, both of which played a decisive. a value of N:P indicated that the investigation of sea water was in the P limit the potential of nutrition. Organic pollution index A value indicated that the investigation of seawater was in mild organic matter pollution. Nutrient and salinity and pH had a significant negative correlation with phosphate negative correlation, which was the most significant, and the various nutrients were were positively related to each other.