Once the pipeline is laid in the body of landslides, part or even the total forces of landslide will act on the pipeline and the pipeline may twist or rupture with fatal demolishment. Taking the K317 landslide in Lan-Cheng-Yu pipeline as research object, the dynamical mechanisms between landslide and pipeline are studied before and after slope excavation by the methods of model test and numerical simulation. The results indicate that stress-relief method is fit for the controlling engineering of landslide when the pipe is laid in the body of landslides with the extending orientation perpendicular to the main slide direction. One or several of gouges, excavated in the upper of the slope, should be paralleling to the extending orientation of pipeline. The optimal depth of excavation ditch and distance for pipeline can be obtained by model test and numerical simulation. The investments of controlling engineering can be decreased largely by using of stress-relief method.