With the increasing of social and economic activities of the human beings, people’s claiming for the nature is also increasing continuously. People’s wanton claim destructs the natural resources, causing debris flow and other geological disasters in the mountainous areas. With the increasing of claiming amount, the geological disasters have also been more and more serious. Debris flow is a kind of joint movement of solid (rock and earth mass) with large grain difference and liquid (water), with the composite and incongruous mixtures of high-concentration water, sand and gravel. Debris flow is a typical disaster geological phenomenon and landform process, which occurs in a short time, but has extremely great destructive power due to huge kinergety. The occurring of debris flow will not only destruct the local regional environment, but will also endanger and threat people’s life security and economic construction. In this paper, taking a region as an example, the author will discuss the development characteristics of debris flow and evaluate its influence on the migration site, and propose preventive and control measures.