Abstract: In order to realize the rapid classification of geomorphologic type，based on the previous research results，using DEM ( Digital Elevation Modeldata) ，the process of extraction of landform information is made．According to the algorithm model，the optimal window of macro topographic factors is obtained by means of mean variation point analysis，eight topographic factors that can reflect the landform information are extracted． The dimensions of each terrain factor are unfied． The correlation coefficient matrix and the optimum combination of topographic factors are obtained by using snow entropy method． The classification of geomorphic types is realized through non-supervised classification by ENVI ( The Environment for Visualizing Images) software． Based on the secondary development platform of ENVI，adopting IDL ( Interactive Data Language) language to implement
program，complete automatic ( half) intelligent and quick division of landform types is realized． Taking the changbai mountain as the research area，from the macroscopic and microscopic classifying landscape，the result of evaluation and analysis of classification results are good． The realization of the system is of great practical significance to the processing and integrating geomorphic types and to the wide range of landform mapping in China．

Key words: digital elevation model ( DEM) data, the environment for visualizing images ( ENVI) software /interactive data language ( IDL) language, combination of the best terrain factors, geomorphology, changbai mountains