Abstract: Based on the monitoring data of the mariculture zone at the Yueqing bay from 2016 to 2018, the assessment and analysis on the marine environmental quality is conducted. The spatial-temporal variation and the relevance of pH, temperature, salinity, DO, Chl a, NH₄-N, NO₂-N, NO₃-N and DIP of seawater in these areas were analyzed and their nutritional status were also evaluated. Assessment by single factor pollution index method revealed that the levels of pH, temperature, salinity and DO in these areas were in accordance with the national second-class water quality standard. Compared with those in other marine aquaculture zones, the DO concentration levels were in the low, and the DIN and DIP levels were in the high. According to TRIX, the eutrophication index of water quality in these areas were relatively high and may be in a state of high eutrophication. The related indexes of the first principal component were NO₂-N, NH₄-N, DIP, temperature and NO₃-N by PCA, and there were positive correlation among NH₄-N, NO₃-N, DIN and TRIX.