Disaster-pregnant environment and watershed morphology are the base of the development and activity of debris flows and therefore, clearly recognizing the disaster-pregnant environment and watershed morphology characteristics has an important realistic meaning to disaster prevention and mitigation. Based on the analysis of the spatial distribution patterns of debris flows in the Bailong River basin, a further study of the characteristics of the disaster-pregnant environment is made from the aspects of regional tectonic environment, topography and geomorphology, formation lithology, precipitation and so on. The coupling relationships between these factors and debris flow distribution are explored. Meanwhile, as to 250 debris flow gullies along the mainstream of the Bailong River, the basin area, length of the main gully, relative relief of debris flow gully and other important parameters are analyzed using mathematical statistics, and the characteristics of basin form in relation to debris flows along the mainstream are identified.