Abstract:HDPE anti-seepage membrane cut-off wall has not been widely promoted yet, but its good anti-seepage performance has been verified in practical projects. According to the project of xx magnetic anti-seepage membrane cut-off wall project, the optimization of anti-seepage membrane cut-off wall,its key technology of magnetic suction anti-seepage membrane cut-off wall construction is studied, including glue magnetic paste, anti-seepage membrane rolling, film laying, treatment of lap joints of anti-seepage membrane rolling, loosening and pulling of locking tube. The results show that during the construction of the magnetic anti-seepage membrane cut-off wall, the adhesive magnetic sticking position must be set in advance. The rolling of anti-seepage membrane must be adjusted according to the order of the anti-seepage membrane. The membrane laying process must be equipped with reasonable counterweights. The lap joint of the anti-seepage membrane must be lamination treated to ensure the effectiveness of lap joints. The loosening treatment time before the locking tube pulled out must be effectively controlled to avoid wall damage or difficulty in pulling out. Combined with the key construction techniques in the construction process, some reasonable construction suggestions are given in order to provide new references for similar projects.