Taking Shanxiu shiplock expansion project in Zuojiang，Guangxi as an example，this paper studies the construction technology of excavation and support of high slope of the approach channel.Combined with the actual construction site and the characteristics of the high slope of the approach channel，the excavation and support methods of the high slope construction are formulated to ensure the safety and feasibility of the project.The research results show that the stability of both sides of the slope can be solved by using this method in the capacity expansion project of Shanxiu shiplock in Zuojiang，which ensures the safety of construction and the normal navigation of the existing channel.