Abstract:This study evaluates the potential and feasibility of measuring, mapping and monitoring of forests damage caused by pine caterpillars (Dendrolimus punctata Walker) using Landsat Thematic Mapper ? data. The composite images using TMS/TM4, TM4/TM3 band ratios with TM2 band are rich in vegetation and forest damage information. The TM5/TM4 band ratios difference data set was found to be strongly correlated with ground-based measurements of forest damage in Zhejiang province. Therefore, it is proved that Landsat Thematic Mapper ? data is sufficient to monitor and detect forest damage caused by insect and diseases.