The scientific assessment and analysis of landscape ecological risks in oasis towns is of great practical significance for optimizing management and control of oasis land resources and maintaining the stability of oasis ecosystem in arid areas. Based on land use data and landscape pattern index, combined with ArcGIS spatial analysis function, this paper studied the temporal and spatial characteristics and influencing factors of landscape ecological risk in oasis towns in Zhangye City. The results showed that the cultivated land and construction land have changed significantly from 1987 to 2018, with an increase of 429.03 km² and 236.26 km², respectively. The overall landscape ecological risk level showed a downward trend and the pattern of high in the north and south while low in the middle. The risk level of each township is positively aggregated in space, and the dramatic change of the estimated risk was also found on the edge of the oasis. Human disturbance is the main factor of risk level change in recent years. The research results can provide decision-making reference for ecological protection and management of oases in arid areas of northwestern China.