The decision tree model was used in this study to assess the landslide susceptibility in Yongjing County over a long time scale of nearly 40 years based on land use over five periods. Evaluation results show that the extremely high and high susceptibility zones of landslide disasters are mainly concentrated around the Yellow River basin (from Yanguoxia Town to Liujiaxia Hy ^-dropower Station) in the middle of the study area, the adjacent areas around Chuancheng Village-Hongquan Town-Wangtai Township in the southwest of the study area, and Santiaoxian Township in the middle east of the study area. The region is densely populated with many human activities. The results of this study are similar to those of previous studies, and the accuracy test with the receiver operating characteristic curve shows that the evaluation results of the five phases are highly reliable. In addition, a negative correlation is observed between the natural vegetation and bare land in the study area and the landslide susceptibility index, while the areas with frequent human activities, such as dry cropland, river area, and urban and rural construction lands, are likely to cause landslide disasters. From the perspective of time, the area of the extremely high and high susceptibility zones decreased yearly, but the reduction rate of the area has significantly slowed down since 2000. The area of urban and rural construction land in the region increased, and that of vegetation decreased during the same period. Hence, the stability of slopes in the region was reduced, and the capability of some disaster prevention measures was weakened. This study provides a reference for disaster prevention and subsequent urban and rural land planning in this area.