Abstract: North China was drought with little rainfall, and became warm earlier in the spring in 2000. Eddy often arrived. From 3 to 9 April three cold eddies continuously brought a great deal of sand-dust to Beijing. In this paper with cloud map data from satellite and results from Model MM5, the source of this sand-dust storm and the mechanism of sand transportation are analyzed. As a result, it is found that air current from upper reaches brought sand-dust through free atmospheric layer. Moreover, sand-dust from the peripheral bare soil was raised from the end of eddy and brought to Beijing.