This study is a preliminary PS-InSAR research for future project in monitoring subsidence by using SAR image acquired by advanced radar satellite. In this paper, PS-InSAR with ALOS PALSAR image is used to evaluate the large-scale surface displacement in central Taiwan mostly covered by vegetation and mountains. The PS-InSAR result is analyzed and then evaluated by comparing with precise leveling data. Both of the displacement patterns are similar to each other. The statistic figure derived from the absolute differences in vertical displacement velocity (DV) vectors on 200 PSs and 200 benchmarks shows that the mean is 1.4cm/year, the minimum is 0.0cm/year, the maximum is 4.5 cm /year and the standard deviation is 1.4 cm /year. The conclusion infers that monitoring large-scale subsidence in central Taiwan by using PS-InSAR is feasible and applicable, and it has a good potential to be realized to a national-level regular project.