There are a series of ecological environment problems in different areas of the Tarim river basin. Affected by irrational human activities

especially by the irrational use of water resource

desertification generally exsited in the lower reaches of the river. Based on the RS information of multiseason （1959

1983

1992）

multiband and multiplatform

depended on the date of GPS positioning

spectral measurment as well as analysis of soil

vegetation and water samples

the desertification maps are produced for different years in Alagan. Moreover

under the support of ARC/INFO software

the dynamic maps of desertification are made. According to the information of GIS DB

system theory

information theory and control theory are used for analysing the processing of desertification in Alagan. At last. based on the model of GM（1

1）

the desertification bend in Alagan is predicted.