Topographic data are critical to global changes in climate,land formations,atmospheric changes,and research in soil and water loss.Recently,NASA released SRTM DEM at 90-meter resolution covering 80% of the Earth's land surface.Prior to SRTM DEM,GTOPO30 (1 km) was the highest-resolution global DEM.As it is a new product,we have no knowledge of SRTM DEM,and so,it is necessary to assess its accuracy.The article introduces apparent accuracy and production procedure of SRTM DEM in comparison with GTOPO30.Further-more,the article analyzes and compares these two DEM datasets at 1 km resolution in Tibet.Results show that SRTM DEM has higher accuracy than GTOPO30.This research can be a good reference for applications in other areas.