Abstract: Remote sensing technology can respond quickly and monitor in real time， and it has become an indispensable means of flood monitoring. There are many large rivers in Anhui Province， and the precipitation is concentrated in the flood season； therefore, the pressure of flood control is great. In the flood season of 2020， Anhui Province experienced extreme flood throughout the whole province，and the Huai River，Yangtze River，and Xin'an River basins are in emergency. The application of space-air-ground integrated remote sensing technology in this flood monitoring is introduced： The space remote sensing technology with domestic high-resolution satellite data as the main data source， the aerial remote sensing technology with UAV photography as the main mean， and the integrated dispatching of ground remote sensing technology with site survey as the main method. These technologies are used together to provide a reliable information source and strong technical support for flood monitoring.