Abstract: China is characterized by complex geological structure, diverse landform types, and a high proportion of mountainous areas. In recent years, under the background of global climate change, a large number of major engineering constructions, unreasonable resource development and human activities have led to frequent occurrences of various geological disasters, which have seriously affected the improvement of people’s livelihood and the construction of a well-off society, and brought about geological disaster risk management and control. Carrying out geological disaster monitoring and early warning research can provide important scientific basis for disaster risk management and control, monitoring and early warning, disaster prevention and mitigation. This article starts with the research on monitoring and early warning of geological disasters in China, focusing on analyzing and discussing the general situation of the development of geological hazards in my country, the existing results of monitoring and early warning and the current research status. Then this article discusses the current research status and practical application of "3S" technology in the monitoring and early warning of geological disasters from the three aspects of the main content, main technical methods, and the development and current status of the main monitoring and early warning models of geological disasters; finally, the application of the current geological disaster monitoring and early warning platform based on "3S" technology in the Three Gorges Reservoir Area and the national disaster prevention and mitigation work is discussed in detail. The final conclusion of this article is that the application of geological disaster monitoring and early warning systems based on "3S" technology in disaster prevention and mitigation in various industries in China has become increasingly mature. The future geological disaster monitoring and early warning system will be based on "3S" technology, integrating observation, research, risk assessment, forecasting and early warning, prevention and management, and organically combining various related disciplines with big data, artificial intelligence, and internet + technology; by simulating the process of geological disasters, analyzing the factors and intensity of inducing disasters, improving the accuracy of the time, location and intensity of geological disaster forecasting.