Onthebasisofthedataofbiologicalandnonbiologicalfactorscollectedrespectivelyfrom1989to1990andfrom1995to1996inthewatersnearbytheQinshanNuclearPowerStation,theecologicalenvironmentandwaterqualityofthewatersareanalyzedandassessedinthepaper.Theresultsshow:(a)thesurveyedareahasthetypicalecologicalcharacteristicsofhightidalrangeestuary,richnutrientsandlowbiologicalproductivity,(b)tide,runoffandoffshoreseawaterintrusionarethekeyfactorswhichresultinseasonalandannualchangesofvariousbiologicalandnon-biologicalfactors,(c)theriskingofseawatereutrophicationindexisresultedfromenormousamountofthedischargesofindustrialanddomesticsewage,(d)becausethesurveyareaislocatedinahightidal-rangeestuary,thermaleffluentfromcoolingsystemdoesnotinducesignificanttemperaturechanges,(e)thefirststageprojectofQinshannuclearpowerstationhasnonotableimpactsontheecologicalenvironmentinthe