To study the technologies of ecological restoration for urban eutrophic lakes, the comparative experiments of different influence for external pollution isolating，sediment covering and macrophytes planting to the average level of water quality and the fluctuating intensity of water body were carried out in Lake Mochou of Nanjing in September 2000. The results showed that it can improve the average level of TN in a relatively short period but it is different to increase the stability of the lake ecosystem through isolating the external pollution by the soft wall； it cannot improve the average level of the water quality or increase the stability of the lake ecosystem either through isolating the internal pollution by covering the sediment； it can not only improve the average level of the water quality comprehensively, but also increase the stability of the lake ecosystem through macrophyte restoration. Further more, algae growth is not positively correlated with nutrient concentration in eutrophic lakes. In a word, to control the eutrophication of urban lakes, it should be done to restore the pristine ecosystem with macrophytes restoration associated with the priority of external pollution controlling.