In landslide survey, the previous survey methods mainly relied on drilling, but the quality of drilling is closely related to the core recovery rate and the level of drilling rig workers. If the core recovery rate does not meet the requirements, it is difficult to determine the position of the sliding surface, and if we want to improve the core recovery rate, it will require a lot of time and cost. If deep displacement monitoring is adopted, the position of the slip surface can be intuitively determined, which not only saves costs but also provides accurate geological data for designers to take reasonable measures, shorten the construction period, and reduce costs. This article adopts the method of deep displacement monitoring to accurately determine the position of the landslide slip surface, which is worth learning from peers.