The Permanent Scatterers technique can reduce the spatial and temporal decorrelation by using a time series of SAR images and it has more accuracy, higher temporal resolution and utilization efficiency compared with traditional D-InSAR. However ,with this technique some limitation should be noticed. For example, only small areas could be processed. Based on the fragmenting method, PS-InSAR map from 1995 to 2000 with high spatial detail and resolution of range displacement was developed in Suzhou area，using radar data collected from ERS-2 satellite.The results validated by leveling surveys indicate that the accuracy of PS-InSAR observations reaches 5 mm. We concluded that for the mapping of land subsidence in urban environments PS-InSAR had a strong potential with regard to cost effectiveness，resolution and accuracy.