Tatun volcano group, the last active volcano in Taiwan, is located in northern Taipei Basin, only 15 km north of the Taipei City. It was previously thought to be a dead volcano, but recent studies show that the last magmatic eruption happened about 5000 to 6000 years ago. The geothermal and seismic activities over the Tatun volcanic area have been highly active in recent years. The geochemical analysis implies the potential existing of the magma chamber under the ground surface of northern Taiwan which has the possibility of re-eruption in the future. In this study, we use ALOS-1/PALSAR images to monitor the surface deformation at the Tatun volcanic area. Stratified atmospheric delay and orbit errors are well considered and corrected by an adaptive patch-based method. The derived displacement history provides a detailed map of surface change with large spatial extent, which is validated by GPS measurements. The results demonstrate the capability of InSAR technique to monitor surface deformation over the volcanic zones.