The Yangtze Estuarine nature reserve for Chinese Sturgeon is an important place for immature Acipenser sinensis.It has significant meaning to analyze and evaluate the eco-environment of Yangtze Estuarine Nature Reserve for Chinese Sturgeon.According to the analysis of the research data in August, 2005 and in May and August, 2006, the evaluation results indicated that the comprehensive quality was at the level of "middle pollution", and the ecological environment in the Nature Reserve was evaluated by the methods of single parameter pollution index, eutrophication index, and biodiversity index.The pollution of DIP in the Reserve is serious and the pollution of DIN is worsened.The eutrophication level in May, 2006 was the highest.The eutrophication level in North Channel of Changjiang Estuary was higher than the other waters in the same period.The phytoplankton biomass is maldistributed and the community structure is simple and unstable.The phytoplankton biomass in August, 2005 was larger than that of level in May and August, 2006.but the level of bio-diversity was lower in August, 2005.Through analyzing the incidental catches of the large-scale Acipenser sinensis, it was found that the environment change and engineering activities formed the potential hazard to Acipenser sinensis.