Information diffusion theory is a good way of information mining and can be used to analyze the information carried by small samples to the greatest degree.Therefore

it is more suitable for the disaster analysis in the small area where usually lacks of enough disaster information.17cities in Anhui Province are selected for the study.A risk measurement model for flood disaster loss rate is established based on information diffusion principle.Probabilities and exceedance probabilities at different damage levels are calculated foreach flood-hit city.Risk zoning map is drawn to make results more intuitive.Results show that overall

Huaihe River basin has the highest risk

followed by the central area along the river.Southern Anhui Province and Dabie Mountains in Western Anhui Province are weak in risk.