Abstract: In this study we analyzed the stability of the Dongmiaojia landslide body in the Xiaolangdi water control project using Flac3D numerical simulations. This landslide body is stable in the normal condition and unstable during heavy rains or earthquakes; in heavy rain conditions, relative large displacements occur to it and may further trigger a fast sliding. From the data of monitoring its surface layer appearances and deep layer deformation for 17 years, we analyzed its sliding trend. Using stability analysis and sliding trend analysis, automatic monitoring schemes were designed and an Internet of Things monitoring system was developed. Detailed monitoring methods were arranged in this study, such as those used for surface and deep deformation, seepage pressure, and precipitation. For the Dongmiaojia landslide body, we recommended a system of three-level failure warning along with a method to determine the warning threshold of rainfall, deformation rate, and other indexes.