Objective: The paper aims to solve the problem of determining the sliding surface of soil landslide, and to provide the basis for landslide stability analysis and prevention engineering.

Methods: In this paper, the sliding surface is determined by field exploration and comprehensively determined by the FLAC3D numerical simulation method. At the same time, Sweden Arc Method and FLAC3D numerical simulation are used to make a comprehensive comparative analysis on the deformation and stability of the landslide.

Results: The position of the sliding surface of dawanjiang landslide is determined by the FLAC3D numerical simulation method, which is located in the eluvium, and the maximum depth is about 7m, which is basically consistent with the speculated position. It provides a theoretical basis for landslide stability calculation and control engineering.

Conclusion: In the determination of the sliding surface and stability calculation of soil landslide, the comprehensive analysis combined with numerical simulation is the more reliable method.