Abstract: This paper based on the landslide deep displacement monitoring data from 3rd High School Landslide in Badong County, analyzing the depth of landslide sliding zone. Making use of the condition of artificial excavation of landslide anti-slide pile, in the process of excavation, comparing the monitoring data with the landslide geological structure and the actual sliding direction and depth of the sliding zone. The results showed that because of the earth's surface influence, the monitoring data have a big accidental error near the earth's surface, while the accuracy is higher for identification of landslide sliding zone in internal landslide. Monitoring the landslide deformation with inclinometer is one of the important means of landslide control design in the future.