Using the observed meteorological data, and typical sandstorm examples at five stations of Wuwei city in east of Hexi corridor in recent 50 years, the climatic background and influence factors of occurring sandstorm are analyzed detail.On the basis of analyzing more than twenties meteorological factors, the sandstorm forecasting equations of various strength, seasons and of areas are set up.The result shows that the sandstorm in east of Hexi corridor is caused by the interacting the drought climate, rich surface sands and strong wind weather in north of Wuwei city;sandstorm days are related to the temperature in winter and string, annually precipitation and strong wind days in mid-and-north-Wuwei city;the sandstorm strength is related to earlier drought, abnormal increasing temperature and strong wind days.