Using visible channels of NOAA satellites，the authors developed a new method to estimate the amount of airborne sand over the arid area in northern China. Due to the great difference in reflectance on the land，it is rather difficult to directly retrieve the dust storm from the visible radiance obtained from the satellite. Considering that the change of the land reflectance is very small during a short time in a fixed place，we can make a comparison between the radiance of the clear sky and that of the dust sky. In this way，we can estimate the optical depth of the dust storm over the land. Test results indicate that，during the dust storm on April 16，2002，the optical depth of dust storm and the airborne sand amount calculated by this method were in agreement with the trend of the synchronous TSP observation.