Dynamic change information of land desertification in the Yellow River Drainage Area was extracted from remote sensing images of three different periods，which include MSS (1975)，TM (1990) and ETM (2000). Investigation shows that land desertification mainly occurred in the northwestern part and the area of land desertification increased 10 653.22 km2  from 1975 to 2000，i.e.，about 426.12 km2 per year. It was the geological and climate conditions that controlled the distribution and dynamic change trend of land desertification. In addition，improper human activity accelerated the desertification trend.