The invention provides a rainfall capacity risk ranking method and apparatus used for geological disaster region assessment pre-warning. The method and the apparatus are used for the geological disaster region assessment pre-warning. The method comprises the following steps of dividing the whole nation into a plurality of points, and calculating accumulated rainfall capacity of each point in a preset time; determining a first rainfall capacity level and a first rainfall capacity ranking weight of each point falling into each province according to the accumulated rainfall capacity of each point in the preset time; dividing the whole nation into a plurality of geological environment regions; determining a second rainfall capacity level and a second rainfall capacity ranking weight of each point falling into each geological environment region according to the accumulated rainfall capacity of each point in the preset time; and coupling the first rainfall capacity ranking weight and the second rainfall capacity ranking weight corresponding to each point, and generating a rainfall capacity ranking graph. According to the method provided by the invention, the influences of rainfall capacity on different provinces and different geological environments are considered at the same time, so that the actual conditions are better met and the potential safety hazards are reduced.