Abstract: Huangtupo landslide, geologically one of the most complicated landslides in the Three Gorges Reservoir area, attracted much attention for being the old site of Badong county. To reveal the true condition of the spatial distribution, mechanical behavior and deformation properties of slip zone in Sub-landslide 1^#, the major and controlling part of Huangtupo landslide, a large-scale investigation tunnel group, combined with boreholes, tests and in-situ monitoring are applied to study the spatial distribution, thickness, formation, physical properties and deformation rules of slip zone. Relatively systematic and comprehensive innovations are obtained during the study. The results show that there are two slip zones in the upper and lower part of Sub-landsldie 1^#. The major lower slip zone is located at the eastern part of Sub-landsldie 1^#, with the elevation decreasing along the main sliding direction. The elevation is lower in the middle and higher in the eastern part. In addition, the spatial distribution of strength parameters show the trend of increasing along the main sliding direction from the edge to front part. The trend also shows in the content change of clay and silt particles along the main sliding direction. As to the deformation distribution, the slip zone at the landslide toe creep slower than the middle edge part of landslide. The deformation response shows spatial svariation to the external influencing factor water level and rainfall.