Abstract: To test and evaluate the capabilities of the large-footprint LiDAR for estimating canopy height in sloped areas,the full waveform data of the geoscience laser altimeter system(GLAS) onboard the ice,cloud,and land elevation satellite(ICESat) were used to retrieve forest canopy heights in Wangqing of Changbai mountains.The forest canopy height was regressed as a function of waveform extent and terrain index in terms of terrain slope ranges.The results show that final regression model for slope category of 0 to 5° could explain 90% variance of forest canopy heights.With the increasing of slope categories,the model performance significantly declines.Generally,for the forest canopy height in the area with terrain slope not larger than 15°,the GLAS waveform data provides reasonable prediction and has great potential for applications.But its capabilities in the areas with terrain slope larger than 15° needs to be further investigated.