Abstract: In the process of ground-based SAR slope deformation monitoring, in order to obtain high quality image and satisfy the need of phase unwrapping, we always need to filter the interferometric phase. Phase filtering can not only improve the signal to noise ratio of the image but also reduce the residuals of interferometric phase image, which contributes to a better phase unwrapping. Thereby the accuracy and feasibility of deformation retrieval can be improved. For the space-variant characteristics of ground-based SAR?interferometric phase image, we studied four classic and efficient ground-based SAR interferometric phase filtering algorithm in this paper. Then ground-based SAR slope deformation monitoring experiment was carried out. Four filtering results of the real ground-based SAR interferometric data were given to compare and evaluate the various filtering algorithms by quantitative and?qualitative?analysis. Finally, the optimal filtering algorithm is given, which lay the foundation for the ground-based SAR interferometric phase real-time filtering optimization and subsequent data processing.