Abstract: Basing on the geological disaster cases information of 2006 -2011, the heavy rainfall observation data and the corresponding radar echo information, the GIS technology and the corresponding radar echo information, the debris flow short - time forecast and early warning technology based on heavy rain type radar echo signal has been researched. Depending on the strongest echo intensity, echo height, strong precipitation echo duration of mass, large, medium and small scale of debris flows, combined with the bottom level of the potential points of geo - disasters information, the index of short - time forecast and early warning of Liangshan has been presented. Basing on the indicated characteristics of the significance and continuity of radar echo signal to the rainfall cloud and the GIS technology, the short - time early warning system of debris flows in Liangshan has been established, which greatly enhances disaster prevention and mitigation, emergency response capabilities, and this has great significance to the geological disasters prevention in Liangshan.