Abstract: The geological structure of Wu'an city is complicated, with intense human engineering activities and developed geological disasters, which seriously threatens the life and property safety of local residents. On the basis of 1∶50 000 geological disaster risk survey data and ArcGIS platform, the authors chose Wu'an City as the study area and adopted a weighted information volume model which includes AHP and information coupling, to construct a risk assessment system based on grid unit. According to different disaster types, different evaluation factors were selected to carry out the susceptibility assessment, and danger assessment was carried out based on the superimposed rainfall factor as well as the susceptibility assessment results. Population, buildings, traffic facilities and other factors were selected to construct the vulnerability model of disaster bearing body. Based on the assessment results of danger and vulnerability, the matrix analysis method was used to complete the risk assessment. At the same time, combined with the characteristics of potential disasters and the actual risk management, the risk zoning was optimized by using the raster generalization function. The results showed that the high risk area was mainly distributed in the north of Huoshui Village and Guantao Village, covering an area of 101.25 km², accounting for 5.61%. The medium risk area was mainly distributed in Guantao Village, Majiazhuang Village and Mine Town, with an area of 796.48 km², accounting for 44.10%. The low risk area was mainly distributed in the gentle terrain such as Yicheng Town and Datong Town, covering an area of 908.27 km², accounting for 50.29%. The evaluation results could provide a basis for disaster prevention and reduction management, territorial space planning and utilization control in Wu'an City, and have certain reference significance for other regions to choose reasonable evaluation methods based on their own actual conditions.