The study of Qinghai Tibet Plat eau has been a focus in geology and geography for researchers home and abroad for a long time.The range of Qinghai Tibet Plateau is different from administrative division.There are many differences among the ranges based on different criterions and purposes.Based on the characters of to pography,we used the data of A ster G DEM and the method of digital terrain analysis to extract the boundary of Qing hai Tibet Plateau semiautomatically with supporting of the ArcGIS,and its to pography was identified and divided automatically.16 kinds of geomorphic distribution maps were acquired.The results showed that the dominating topographies were high-elevation hills,low-relief high-hill, middle-relief subalpine and middle-relief high-hill,the areas accounted for 60.58% in Qinghai Tibet Plateau.The terrain was quite gently in inner plateau,had a little large relief in marginal area,indicating significant difference between plateau and the adjacent regions into pography.