Abstract: Because of the disadvantages of the single evaluation method in the risk assessment of geological disasters, the methods of slope unit and combination weighting were adopted to carry out the risk assessment of geological disasters. Geological disaster risks could be classified into four grades of being extremely high, high, middle and low danger zones in Dongchuan District, by using ArcGIS platform and hydrological analysis to build slope units and choose 9 evaluation factors such as slope gradients, slope directions, distances from the highway, distances from the river, distances from the fault, lithology, rainfall, elevation, and land use type, and by adopting the combination weight—combination of analytic hierarchy process (AHP) and entropy weight method—to determine the comprehensive weights of evaluation factors. The results show that the slope units could well reflect the microcosmic geomorphologic characteristics; the results of zoning danger regions were consistent with the actual distribution of geological hazards; the middle, eastern and northern parts of the study area demonstrated dense distributions of geological hazards, fragile geological environment, obvious human activities and high risks of geological hazards.