Through adjusting the position of the closure gap of Caofeidian southeast seawall cofferdam and adopting the layered construction method,we improved the safety of closure construction.Applying the double-layer geotextile cushion method,we enhanced the seawall's stability against sliding.The closure construction was implemented successfully under the condition of 2.37 m fall head,4 m/s average speed of cross-flow and 6 m/s maximum instantaneous flow speed,and the construction cost was cut down.