Abstract: Speckle filtering in polarimetric synthetic aperture radar (PolSAR) images is an important step for the extraction of meaningful information from PolSAR images. In order to evaluate quantitively the preservation performance of polarimetric information for PolSAR speckle filters, the paper presents an effect evaluation method of PolSAR speckle filtering based on difference degree. This method compare for difference degree of targets area which from original and filtered PolSAR images, it can achieve quantitative evaluation for the preservation performance of polarimetric information. In evaluate process, adopt to averaging difference degrees from pels to pels on target area, instead of conventional method which always averaging Kennaugh matrices to calculate polarization signatures. This amelioration can avoid second estimate to Kennaugh matrices, obtain more accurate result of evaluation for speckle filtes which performance are similar evaluated by polarization signature. Finally, three typically PolSAR speckle filtes are used to filter simulate and real PolSAR data respectively. The experiment evaluate results of areas and point targets show that the proposed algorithm has the well theoretical and actual performance in effect evaluation of PolSAR speckle filteing.