Abstract: In the China-West Germany joint research project of Remote sensing monitor of desertification enviroment in the Daxintala region we used MSS, TM and CCT data of Landsat. Computer processing of remote sensing digital images was done in Germany. Processing results have been checked in field. It is generally recognized that the results are consistent with charateristics of desertification elements and favourable to com-pile existing state map of desertification. Remote sensing digital images are the reflections of spatial distribution of ground radiant energy.In order to use images to analyse and interpret desertified environment element one must carry out computer processing to the image data, thus we can draw out interesting information concerning desertification and use them to compile thematic map of desertification. Remote sensing digital image processing is not only a single technigue but also a comprehensive anlysis of many kinds of information and feedback process. The perpose of computer processing is to use mathematic methods to determine corresponding relations between images and thematic elements of desertification. Computer digital processing of remote sensing images was finished in Berlin Eree University Institute of Applied Geology Remote Sensing Division by means of Computer System GE ISI of Interpretation System Incorporated.