Based on the water quality data collected from the Maowei Sea in 2008,the nutritional status is assessed by using eutrophication index,nutrition quality index,and organic pollution index.According to the pollution sources in 2007,the sources of nutrients are also analyzed.Results show that the Maowei Sea is seriously polluted by inorganic nitrogen,and the water quality is at eutrophic state.The organic pollution degree remains in the second level.The content of nutrient is relatively high in the north and the east of the Maowei Sea.The inputs of total nitrogen and total phosphorus through the Qin River and Maoling River are the main sources for nutrients,which account for 79% of the total nutrient discharge,followed by the mixed sewage outfall.Results also show a significant correlation between the load of nitrogen(or phosphorus)and the nutrient concentration in seawater,and the correlation coefficient is 0.873(or 0.824).