Abstract: This paper is based on the extraction and analysis of Majiagou landslide's surface, boundary and drilling information in the Three Gorges Reservoir Area. It uses GIS spatial interpolation and grid computing, combining with the mechanical formula. It then calculates and zones the stability of Majiagou No.1 landslide. First, it gets the preliminary form of the slip surface shape, which is based on proceed spatial interpolation with the known two slip plane drilling information. Then it speculates the sliding surface information of the rest four drilling with the comparison of the slip surface and the remaining four drilling stratum information. Finally, it gets the whole slip form, based on proceed spatial interpolation with all drilling information. After comparison, it analyzes the spatial interpolation methods of determining slip plane space form. It puts forward that based on a small amount accurate information of slip surface, the result can be more in line with the actual situation when using the radial basis function interpolation. It assumes that the groundwater level in the landslide body and the reservoir water level are the same. It uses the formula of infinite slope safety factor in the ArcGIS raster calculator to obtain the safety coefficient zoning map of Majiagou No.1 landslide without considering the interaction between grid columns. The calculation result shows that the unstable area of Majiagou No.1 landslide mainly concentrates in the leading edge of the sliding body, while the relatively stable areas are distributed in the front, middle and rear middle parts. And as the water level rises, the slope safety factor has a certain degree of decline. Especially the landslide leading edge can be a part of the reservoir water immersion. So the key protection governance position can be divided for Majiagou landslide, which can provide valuable reference for the prevention and treatment scheme of Majiagou landslide.