在今年发生特大洪水期间，中国遥感卫星地面站利用加拿大的民用微波雷达卫星（Ｒａｄａｒｓａｔ），自７月中旬开始，对长江和嫩—松流域进行了动态频度平均３天的全流域性重复监测，对有关部门及时掌握洪涝态势起到了重要作用。文中介绍了雷达卫星ＳＡＲ的技术特点及其在今年洪涝灾情快速反应中的作用。 During the extraordinary floods this year, China Remote Sensing Satellite Ground Station utilized Canada’s civil microwave radar (Radarsat). Beginning in mid-July, the Yangtze River and the Nen-Song basin were dynamically frequency-averaged over three days , Which has played an important role in timely grasping the flood situation by relevant departments. The paper introduced the technical characteristics of radar satellite SAR and its role in the rapid response of floods in this year.