In view of the close distance between Shuangqiao junction and Xinjianghai junction in the Xinjianghai River waterway，the small water level difference，and the long normal level period in the upstream and downstream，this paper carries out the technical and economic analysis of retaining or canceling the Shuangqiao cascade scheme.The results show that canceling the Shuangqiao cascade scheme has a great influence on regional flood control，drainage，water system connectivity，and water quality.The total investment and the operation cost of the water system restoration project are high，and the internal rate of return of the project is low.In contrast，retaining the Shuangqiao cascade scheme to maintain the existing water system layout can ensure that the ship lock can be opened and jointly dispatched with the ship lock of the Xinjianghai River，so as to share the anchorage to be locked，which is economically reasonable.