First，this study analyzed the trend of TN and TP in water according to the water quality indexes of Daning regulating reservoir for the past three years.Secondly，this study discussed the effect of enhancement and releasing on water quality indexes(especially N/P)based on the result of investigation of N/P contents in fish over three years old in the Daning regulating reservoir.Finally，some suggestions about enhancement and releasing were made in order to improve the water quality and aquatic ecology status.This study may be used to provide some reference to eliminate the risk of eutrophication in Daning regulating reservoirs and improve the safety protection of urban water supply in Beijing.