| Sand and dust storm mainly occurs in deserts and its neighboring arid and semi-arid areas. It results from three factors of climate, environment and human activities. The characteristics of surface, such as geomorphic pattern, vegetation coverage, snow cover, soil moisture and soil freezing and thawing, conduct a great influence on the dust storm. But the studies of between them are relative rare and most of them are not quantitive.In this paper, we choose midwestern Inner Mongolia as the study area, which ranges from 38°N to 44°N and from 106°E to 113°E. By using the NDVI data of NOAA/AVHRR and meteorological observational data in sand and dust storm processes, the characteristics of earth surface and the relationship between them and the sand and dust storm and its influence on the sand and dust storm was analysed respectively. Meanwhile, by using a dusty weather numerical prediction model, the numerical studies on the influence of sand sources in Inner Mongolia and the surface heating flux on the sand and dust storm was performed. The results show that in the areas:(1) There is a close relationship between the geomorphic types, sectional lines of the terrain and distribution of sandstorm days. The sandstorm occurring days in midwestern Inner Mongolia can be listed from the most to the least in the following order: desert border and sands, higher plain, mountains and hills, and lastly the plain regions.(2) There is a negative interrelation between the days of sandstorm and the percentage of coverage of vegetation, which varies due to the difference of geomorphic feature and the changes of season. The negative interrelation between the percentage of coverage of vegetation in summer in sand covering area and the days of sandstorm in the next year is of the most.(3) Along with the decreasing soil volume moisture, the occurrence of dust storm will increase. But only when soil volume moisture lower than 0.20, it is in evidence. So this value can be seen as a threshold value. (4) There is a negative interrelation between sand storm days and snow cover days or snow cover percentage, which varies due to the difference of climate feature and the change of season. The negative interrelation between sand storm days and snow cover days in winter is more marked than in early spring. The negative interrelation in semi-arid climate region with low temperature in early spring is more significant than in other regions.(5)There is a negative interrelation between sand dust storm days in spring and the end day of soil surface freezing, which varies in difference areas. (6) Before the dust storm accurrence the accumulative surface heating can induce the surface potential temperature rising evidently and favor for the dust storm. In the desert and high plain areas the surface heating touches the maximal value just before the dust storm breaks up while in the plain and foothill areas it does not. So for the former the influence of suface heating on the dust storm is more efficient than the later. (7) The surface heating flux can induce the surface wind speed, friction velocity, and stratification stability strengthening at day and weakening at night and so bring the fluctuating of dust storm intensity. Moreover, the influence of surface heating can spread from the PBL upward to the middle troposphere (500hPa) and enhance the strength of ascending motion. (8) There are three preponderant dust transportation layers, namely 500hPa, 700hPa and in the PBL, in northern China. Both of the dust particles from the Mongolia and midwestern Inner Mongolia are transported eastward at 700hPa and southward under 850hPa. But the former can only be transported southward to the Huangtu Plain while the later to north of the Changjiang river. The primary characteristic of dust transportation in northern China can be indicated that the higher the dust particles are raised, the stronger they are tranported eastward. Contrariwise, the southwards transportation is strong. Meanwhile, the more northern the dust particles rising, the stronger they are tranported eastward. Contrariwise, the southwards transportation is strong. And the zone from 40°N to 42°N is the dividing line.The main discovers of this study are as follows:(1) With respect to the decreasing soil moisture, occurrence of dust storm increased only when soil moisture was lower than 20%, which showed as a threshold value of soil moisture in evidence. For the surface wind speed, the value is 3.5m/s. There is a negative interrelation between the days of sandstorm and the percentage of coverage of vegetation, which varies due to the difference of geomorphic feature and the changes of season. The negative interrelation between the percentage of coverage of vegetation in summer in sand covering area and the days of sandstorm in the next year is of the most. There is also a negative interrelation between sand storm days and snow cover. This negative interrelation in winter is more marked than in early spring, and in semi-arid climate region with cool temperature in early spring is more significant than in other regions. The negative interrelation between sand storm and snow index which consider snowcover scope as well as snowcover day is more significant.(2) In the desert and high plain areas the surface heating touches the maximal value just before the dust storm breaks up while in the plain and foothill areas it dses not. The surface heating can induce the surface wind speed, friction velocity, and stratification stability strengthening at day and weakening at night and so bring the fluctuating of dust storm intensity.(3) In northern China there are three preponderant dust transportation layers, namely 500hPa,700hPa and in the PBL. Both of the dust particles from the Mongolia and western Inner Mongolia are transported eastward at 700hPa and southward under 850hPa. But the former can only be transported southward to the Huangtu Plain while the later to north of the Changjiang river. The primary characteristic of dust transportation in northern China can be indicated that the higher the dust particles are raised, the stronger they are tranported eastward. Contrariwise, the southwards transportation is strong. Meanwhile, the more northern the dust particles rising, the stronger they are tranported eastward. Contrariwise, the southwards transportation is strong. And the zone from 40°N to 42°N is the dividing line.
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