The three-parallel-river area is referred to as the parallel drainage basins of Nujiang,Lancang and Jinsha rivers,where debris flows occur frequently.Based on analyzing the characteristics of debris flow disasters occurred in this area,five indexes including slope,lithology,fracture,vegetation and human activity, were chosen as the evaluation indices of debris flow hazards.Supported by ArcGIS,databases of debris flow hazard assessment,graphics and attribute tables were established.The study developed models for risk assessment and obtained the hazard zonation map of the area by normalizing,classification and weighting the evaluation factors.The results agreed well with the actual debris flow events and can provide an important basis for identification the potential disaster targets,optimization of disaster prevention measures and disaster reduction policy making