Abstract: Based on the soil data of the year 1985, Landsat TM images of 1998 and CBERS images of 2008, we reconstructed three-period distribution of soil salinization through interactive machine-artificial interpretation. Then the spatial-temporal changes over the past 23 years were analyzed with the support of GIS spatial analysis methods. The results are shown as follows. (1) With the expansion of arable land, salinization of arable land increased, too. Soil salinization land increased from 13.32×10⁴ hm² to 13.78×10⁴ hm². (2) Soil salinization is widespread, mainly in the lower edge of the oasis, the river downstream and the low-lying flat terrain areas. Salinized arable land presents a bar-shape distribution inside the oasis and a patch-shape distribution outside the oasis. (3) The expansion of soil salinization of Weigan River Basin was primarily caused by factors such as the increasingly drier climatic changing trend, river, canal and reservoir leakage, irrational farming, and the fact that the land is not flat. However, it has been alleviated by the implementation of ecological restoration and amendment of reclamation.

Key words: driver forces, soil salinization, spatial-temporal changes, weigan river basin