三峡工程第三期截流工程是确保实现初期围堰挡水发电及同时修建右岸大坝和电厂的关键性工程。三期截流采取单戗单向立堵截流，其特点是截流落差及龙口流速均较大。通过水工模型试验成果，分析了影响截流落差的因素，并研究了非龙口段进占及龙口段进占中有关截流技术问题。 The closure of the third phase of the Three Gorges Project is a key project to ensure the initial cofferdam power generation and the simultaneous construction of the right bank dam and power plant. The third phase of interception to take a single 立 unidirectional vertical blocking interception, which is characterized by intercept closure and Longkou flow velocity are larger. Based on the results of hydraulic model test, the factors affecting the closure drop were analyzed, and the relevant technical problems of closure in the non-long mouth section and the longkou section were studied.