Based on the 151 ancient city sites from the Western Han Dynasty to the Ming and Qing Dynasties in the Hexi Corridor of Gansu Province, GIS（geographic information system） spatial analysis method was used to study the spatial and temporal evolution of ancient city sites and their distribution characteristics in the Hexi Corridor. The results show that the city sites in Zhangye City have the highest distribution numbers, and county-level city sites are the most numerous grade.They are concentrated in Zhangye City, Jiuquan City, and Wuwei City, the distribution of city sites in each period exists certain unevenness and concentration, which is mainly manifested in the Ming and Qing Dynasties, and may be related to the better preservation of the period. Zhangye has experienced multiple periods of high density nucleus of city sites,the directional trend and concentration trend of the distribution orientation of city sites become increasingly obvious with the distribution of time, showing a tendency of “east-southwest-northwest”.