Abstract: In this study,the hierarchy analysis,GIS means and normalized values of 9 evaluation factors,such as loose material surface density,stratigraphic lithology,tectonic fracture density,seismic density,slope aspect,soil erodibility,land use type,slope length and gradient,gully bed slope and gully density,and average annual rainfall,were used.The purposes of the study was to develop an assessment model for debris flow susceptibility along the Yangtang river reach in Shimen Township in the Bailong River Basin.Finally,the grid diagram of assessing debris flow susceptibility in the study area was divided into 4 grades.The results showed that the proportion of the areas with high debris flow susceptibility accounted for 51.04% of the whole study area,and the areas with mid-high debris flow susceptibility accounted for 68.71%.The debris flows were distributed along the large active fault zones,especially in the zones with intensive secondary fractures and small folds.They were also distributed along the slidable strata,especially in the zones with dense gullies.Debris flow occurred easily on the slopes with high soil erosion.The results were tested by the database of debris flow in the study area.

Key words: debris flow, susceptibility assessment, analytic hierarchy process, model development, Bailong River Basin