Abstract: Early warning of geo-hazards based on meteorological factors has played an important supportive role in disaster prevention and mitigation in China since its inception in 2003. This paper summarizes the the 20-year development process, technical methods, and disaster reduction effects of the early warning works. (1) The development process of early warning work process is divided into three stages: initiation and promotion (2003-2009), deepening cooperation (2010-2017), and reform and enhancement (2018-2022). (2) With 24-hour early warning work as the main content, a progressive warning model and a relatively complete warning service system have been gradually formed. (3) Three sets of early warning model technology and method systems have been gradually developed, including critical precipitation threshold model, the threshold model based on geo-hazards risk, and the dynamic early warning models, with the publication of industry standards for warning. (4) The spatial and temporal accuracy of warning products continues to improve, with the national and 26 provincial warning spatial accuracies exceeding 5 km × 5 km. The focus is on 24-hour warnings, with development towards 72-hour and medium- to long-term forecasts. Over 8 provincial-level and some municipal and county-level authorities have implemented 3-hour short-term warnings, gradually forming a work system to support service short impending warning response, medium-term prevention and long term deployment. (5) Where there is warning, there is response. The Ministry of Natural Resources has taken the national early warning as one of the bases for initiating defense responses, and 18 provinces have clarified the working mechanisms of the early warning response linkage. (6) The awareness of multi-party disaster prevention has been continuously enhanced. With strengthened inspections,evacuations, and successful risk aversion after receiving early warning information, the effectiveness of disaster prevention and mitigation is evident. The experience of early warning works in the past 20-year can provide reference for the next step in promoting the early warning of geo-hazards based on meteorological factors, supporting the enhancement of China’s capability and level of geo-hazards prevention and control work.