Abstract: The study found that the construction environment of the dam impervious wall, the reliability of the concrete and slurry mixing system, the concrete construction process and construction technology all have an important influence on the construction quality of the dam's concrete impervious wall. In order to improve the quality of the cut-off wall, this article takes the construction of the cut-off wall of the Gangu Dazhuang Project as an example, briefly describes the construction technology of the cut-off wall of the dam, in order to provide a reference for similar projects.