Abstract: SAR Differential Interferometric Technique(D-InSAR) is an extension of Synthetic Aperture Radar(SAR).The radar image of differential interferometry can be used to detect the crustal deformation at centimeter scale or even more accurate.It has the advantages of all-weather and wide area in monitoring settlement of ground surface and subsidence of mine.Based on the monitoring for subsidence in Wu'an mine and settlement in Cangzhou area,the application of the new technique in natural calamity monitoring is introduced.