In this paper,a geohazard monitoring and management system for large-scale reservoir involving the obtaining,management, analysis and expression of geohazard monitoring data, is constructed based on IoT (Internet of Things),3D WebGIS and spatial database technology.Firstly,we construct a sensor network for geohazard monitoring according to monitoring parameters and get remote monitoring data.Secondly,in true geographical environment of 3D network,we can realize 3D network expression and interactive application of real-time monitoring results,as well as simulation analysis of geohazard.Landslide monitoring and management in Danjiangkou reservoir area are taken as examples.The results show that,the system is stable,effective and intelligent,and the system can support landslide monitoring and management in the reservoir area and it has a good application prospect.