Abstract: Physical mechanism of sand particle uptake and vertical transport is analyzed comprehensively based on micrometeorological and particle size distribution data collected in both sides of Helan mountain from 1996 to 1999. The discussion is composed of dynamic forcing of intensive wind, thermal instability and sand particle source. Updraft characteristics of mesoscale weather system, calculating methods of sand particle terminal velocity, turbulent features of sand surface, vertical wind speed, the int ensity and frequency of superadiabatic gradient and humidity inversion and sand particle size distribution of desert are analyzed. The effects of surface characteristics and water content of sand on uptake wind speed of sand particles are also discussed.