There has been rapid change in the landuse in Muara Gembong, West Java in the periods between 1976 and 2018. The goal of the study is to analyze the impact of coastal land used alteration on changes in the extent of mangrove area and shoreline dynamics in Muara Gembong within 42 years. To detect the changes in landuse, several Landsat satellite images acquired by MSS sensor of Landsat 2, TM sensor of Landsat 5, the ETM+ sensor of Landsat 7 and OLI sensor of Landsat 8 were used. For shoreline dynamics, the Digital Shoreline Analysis System (DSAS) 4.3, an extension toolbox of ArcGIS was applied. The result of multitemporal temporal data analysis showed that the area of mangrove forest in Muara Gembong has decreased more than 60% in the period of 1976-2018 converted into extensive aquaculture of shrimp/fish and settlement. This massive land conversion has also lead the shoreline changes and abrasion rates in some coastal villages are very severe. This study will be useful in providing necessary information for effective ecological mitigation program to protect the coastal area of Muara Gembong.