Abstract:Interferogram of two coregistrated master and slave images is one of the main products in the SAR interferometric processing, and the filtering of interferogram is a key step for rational unwrapping. So the quality of interferogram can not only be applied to assess the coregistration precision, but also be used to determine the filtering factor and assess the filtering effect. According to the basic principle of the method of sum of phase difference (SPD), this paper puts forward the phase difference and index with considering the 2π discontinuity and weighted phase difference and index,where the weight is determined by coherence value. This quality map can assess the interferogram with 2π discontinuity and highlight the low coherence area. Finally,the advantage of this quality index is proved by the DEM interferogram of the Xi’an area taken as an example.