Interferometric Synthetic Aperture Radar(InSAR) is an effective method form on monitoring surface deformation,especially the applications in monitoring the ground subsidence by means of D-InSAR and PS-InSAR.Both D-InSAR and PS-InSAR were applied to the computation of Suzhou's land subsidence volume,and the results computed by the two different methods were compared with subsidence data measured by leveling.The different characteristics and suitable and unsuitable applied conditions of D-InSAR and PS-InSAR on monitoring Suzhou land subsidence were indicated on the basis of specific application in Suzhou area.