To explore the impact of the spatial distribution of material sources within a watershed on the susceptibility to debris flows. The nearest neighbor index was adopted, based on the principles of mathematical statistics, to quantify the spatial clustering of material sources. Using 2243 small watersheds as evaluation units, the longitudinal gradient, area-elevation integral, topographic wetness index, peak ground acceleration of earthquakes, and rock hardness were taken as disaster-prone indicators, and the aggregation index of material sources, connectivity index, and material reserves were taken as the core material source indicators. The LightGBM model was relied on to investigate the susceptibility to debris flows in the Shigu-Gangtuo section of the upper reaches of the Jinsha River. The research process calculated the index system of material source factors and the index system without material source factors. Both results indicate that the high and very high susceptibility areas are mainly concentrated in the Benzilan-Batang section. The receiver operating characteristic curve(ROC) curve analysis shows that after incorporating the material source characteristic indicators, the area under the curve(AUC) value increases by 6% compared to the AUC value without material source characteristics, indicating that the model performs well and has high predictive accuracy after the inclusion of material source indicators. It also proves that the material source characteristic indicators are highly correlated with the probability of debris flow occurrence.