Abstract: Bases on the investigation results of the coastal water in Changli Golden Beach National Ocean Nature Preserve from 1999~2013, the annual and seasonal variation of nitrogen and phosphorous, nutritional structure and its influence factors were analyzed and discussed. Also the potential eutrophication was evaluated. Results show that the content of the nitrogen and phosphorous nutrient salt shows a declining trend, with high volatility in recent years. The content is high in summer and low in spring and autumn. Its temporal and spatial distribution characteristic is consistent with growth rhythm of phytoplankton and seasonal variation of surface runoff. The nutrient level is generally at poor nutritional status in this area, and there has been several times of eutrophication in separate years, the level of nutrient is biased towards phosphate limit.