In the past decades, researchers have successfully rebuilt the digital elevation model (DEM) using such Interferometric synthetic aperture radar data (InSAR) as SIR-C/X SAR and ERS1/2. As a new generation of synthetic aperture radar, Phased Array type L-band Synthetic Aperture Radar (PALSAR) , which is onboard Advanced Land Observing Satellite (ALOS), works at a longer wave length-L band. Its penetrating depth is deeper than the radars that work at C band. Thus it has advantages in the construction of DEM. However, there have been few reports about the DEM extraction from this technology. The open source program-package ROI_PAC version3.0 provided by NASA/JPL can be used to rebuild DEM from PALSAR Level 1.0 data that is not calibrated. Therefore, ROI_PAC version 3.0 was modified in this study to make it rebuild DEM from PALSAR Level 1.1 data. The workflow of ROI_PAC was described. The method introduced in this paper was validated by a set of PALSAR Level 1.1 data. A comparison between InSAR DEM and reference DEM was made. The difference between them is 0.27 m, with a standard deviation of 9.24 m. There are more than 80% pixels having height errors within 10 m. The results show that the method proposed in this study is useful.