This paper is based on the data of sandstorm occurrence days of each month and year and its climatological data,such as gale days,temperature,rainfall,the environmental data,agricultural acreage and green area in the corresponding period in Jingtai County,Gansu Province from 1957 to 2006 using some statistical methods,such as Mann-Kendall,moving-t test,simple linear regression and multiple linear regression to analyze the causes of frequent sandstorm in Jingtai and its interannual sudden change characteristics and weight-sort the impact factors of it. The conclusion is that: in the past 50 years,the occurrence days of sandstorm in Jingtai County has a sudden change in 1984; the occurrence of sandstorm has a significant positive correlation with the frequency of the gale and has a significant negative correlation with the total green area,the lowest temperature,the total agricultural acreage and the rainfall in spring. Jingtai County's special geographical position,landscapes and the dry-and-windy climate contribute a lot to the frequent sandstorms. The above study result is very important theoretical and practical significance for reducing the disaster loss caused by dust storms.