Abstract: Firstly, a formulation of the phase constituent of interferometric SAR is presented, which is important tounderst and the data processing of interferometric SAR; secondly, data processing methods of interferometric SAR are compared and analyzed, furthermore, some problems that should pay attention to when the data processing are implemented are introduced. At last, basedon the EAR-1/2 interferometric SAR data before and after the Mani earthquake with M= 7. 5 on 8 Novem ber 1997, this paper introduced the ba sic theory that use differential interferometric SAR to extract the surface deformation field.

Key words: Differential interferometric SAR, Differential interfero gram, Coseismic displacement field