In order to study the atmospheric stratification characteristics and the thermal structure of sandstorms,we performed an intensive observation during the passage of strong sandstorms process in Minqin,Gansu province from 23rd to 24th May 2004,by using the L-band radar sounding.The vertical profiles of meteorological elements and energy synoptic meteorology are used to analyze the characteristics of the atmospheric stratification and the evolutional characteristies of the atmosphere during the development process of the sandstrom.The results are as follows:Before the sandstrom arrived at Minqin,the wind speed below 500 hPa was small,there was the easterly flow below the 800 hPa level and the westerly flow at the middle-upper level.When the sandstrom passed through Minqin,the wind speed increased apparently in the surface layer,below the 700 hPa level was the northwesterly flow and the southwesterly flow in the upper atmosphere.The high-layer relative humidity was higher than that of the low-layer atmosphere before the passage of the strom,however after the passage,the relative humidity increased obviously,and there was a humidity inversion phenomenon near 800 hPa.Around the passage the entire atmosphere had a vertically consistent trend of humidity.The surface temperature was higher before the passage,there was a super low temperature phenomenon near 200 hPa,and a thicker subsidence inversion layer near 250 hPa,along with the passage of the sandstorm,the temperature in the lower level dropped markedly,the temperature inversion layer near 250 hPa gradually weakened and another temperature inversion layer occurred near 800 hPa.Before the passage,there were low pressure,high temperature and weak wind near the ground surface,when the storm arrived at Minqin,the pressure surged up,the wind speed rapidly increased,and the temperature dropped.The atmosphere was convectively below 500 hPa before the passage,during the saturation energy deficit reduced gradually,the unstable energy was transferred from upper layers to low layers,the development of vertical motion was intensified.After the passage,the whole atmosphere was stable,the unstable energy was used up,and the whole atmospheric humidity increased greatly.