摘要： This study aims to mapping the level of degraded land of mangrove forest area In TUGU Sub-district, Semarang, by comparing the results between the Landsat 7 ETM + images of 2009 and ALOS AVNIR-2 in 2009. In determining the degradation of mangrove forest area, we used geographic information systems and remote sensing as a tool of analysis that is based on three (3) criteria; land use type, canopy density, and soil resilience from abrasion. From 2 satellite image data used, it will be supervised image classification using ER Mapper software to get the criteria type of land use and density of the canopy. For soil resilience from abrasion, we used soil types reclassification techniques, using ArcGIS software. Based on Landsat imagery, obtained results 92.22 % of mangrove forest area included in severely damaged condition and 7.78% is included in the category of moderate damage. Meanwhile, based on the results of ALOS image, 77.73 % of mangrove areas in severely damaged condition and 22.27 % are included in the category of moderate damage. From this study, it can be concluded that ALOS and Landsat Imagery is good for the determination and identifying critical mangrove area and distribution of mangrove forests, but the degraded land of mangrove maps generated by Landsat, less detailed than ALOS in classification and representation the conditions of critical mangrove area in Tugu sub-district.