Hengduan mountainous area in southwestern China is highly susceptible to debris flow hazards. In order to investigate the spatial distribution of 7181 debris-flow-prone catchments, the area has been classified into six natural geographical subregions based on its climatic, geological, and geomorphic types. The spatial analysis reveals that their spatial distribution exhibits a significant difference in the six sub-regions. The sub-regions with East Asian monsoon climate have a higher density of catchments than other sub-regions with Tibetan cold climate. The highest density is 286 catchments per 10,000 km2, seven times the lowest sub-region. The DFCs are clustered in Dadu River basin, Minjiang River basin, Yalong River basin, Jinsha River basin (Mainstream below Shigu), and Jinsha River basin (mainstream from Zhimengda to Shigu). The climatic factor is more important than the other factors. The histogram of the catchments with average annual rainfall shows that the regions with an annual rainfall of 800–1050 mm are more prone to debris flows. Relative elevation, mean slope, and landcover were chosen to examine the distribution of the debris flow catchments along with geomorphologic factors. It is found that the sub-watersheds within 3 km from faults and 5 km from the main river in 0.10 g, 0.15 g, and 0.2 g PGA class with a relative elevation of 1000–2000 m, mean slope of 15–25°, and woodland cover are the most highly susceptible to debris flows.