The conventional repeat-pass differential SAR Interferometry (D-InSAR) was proved to be a remarkable potential technology for mapping surface deformation. However, a full operational capability has not yet been achieved due to phase decorrelation and atmospheric disturbances. A stacking differential interferograms strategy is presented for surface deformation rate derivation in this paper. In this algorithm, the pixels that preserve a good coherence level in the whole interferograms stack are identified to generate the triangulation network with Delaunay criteria. The Minimum Cost Flow (MCF) algorithm is used for phase unwrapping of individual interferogram. The unwrapped phase series of each point is used to estimate the linear deformation rate, and the standard deviation of the estimates of the linear subsidence rate is calculated to indicate the nonlinear subsidence of the pixel. The algorithm was tested with 9 scenes ASAR data acquired from 2004 to 2005 to derive the linear subsidence rate of Langfang City.