Abstract: In order to understand the pollution degree and eutrophication status of coastal waters of Zhuhai city, the water quality of this sea area was investigated and monitored in November 2017 (autumn) and March 2018 (spring). The single factor quality index method, organic pollution index method and eutrophication index method are used to evaluate the eutrophication level of the sea area. The results of single factor quality index evaluation showed that the overall water quality of the coastal waters of Zhuhai city was extremely poor. The proportions of the four inferior seawaters in spring and autumn were 90.28% and 79.17%, respectively. The DIN and DIP exceedance rates were 94.00% and 28.00% in spring, and 89.00% and 78.00% in autumn, which were the main reasons affecting the overall water quality. The DIN/DIP ratio of the whole area was higher than the Redfield ratio, which was in the phosphorus limit state. The results of organic pollution index evaluation showed that the proportion of serious organic pollution stations was 51.39% in autumn, 56.94% in spring, and the pollution coverage was wider in spring. The eutrophication index evaluation showed that the proportion of severe eutrophication stations in spring and autumn was 30.56% and 31.94%, respectively, and the proportion of severe eutrophication stations was 6.94% and 25.00%, respectively, indicating that the eutrophication was high. There is a significant positive correlation between the eutrophication index and COD_Mn, and a significant negative correlation with salinity, indicating that COD_Mn can reflect the eutrophication status of Zhuhai coastal waters to a certain extent. The higher the salinity is, the lower the level of eutrophication level is, which indirectly proves that eutrophication is mainly caused by land-sourced pollutants and is related to the physical mixing process of runoff and ocean currents in the open sea.