Thermal and "Speckle"noise is an obstacle to get digital elevation model（DEM） from the interferogram by 2-D unwrapping of interferogram phase. An adaptive filtering method for synthetic aperture radar（SAR）interferometric phase images is presented in this paper. Based on sixteen directional masks

which are the enlarged Prewitted edge masks

the fringe direction can be determined. Then those pixels on the same direction is filtered by average phase filtering method to generate filtered phase value. In fact

the change of interferogram phase is a gradual change. The pixel’s direction can be selected from the neighbouring directions of the preceding pixels in order to avoid too many computation about the directions of the present pixel. This method is useful

especially for tightly packed fringes. The method can be carried out easily. Using interferograms generated by SIR-C/X-SAR repeat-pass

its effectiveness is tested.