Abstract: Based on the typical debris flows in Nyingchi, this paper presents the basic type, distribution and movement of debris flows, analyzes the initiation condition and critical threshold, and discloses the incubation law of debris flows, and also the impact of temperature and rainfall changes on debris flow initiation. Glaciers debris flow may be inspired during temperature or rainfall increasing. If daily precipitation < 5 mm, melting ice and snow debris is stimulated mainly by temperature; when daily precipitation is 5-10 mm, mainly the glaciers-rainfall debris flow occurs; when daily precipitation >10 mm, rainfall debris flow is in dominate. Glacier debris flows under temperature increasing and decreasing account for 80% and 20%, respectively, while the rainfall debris flows account for 60% and 40%, repectively. Much rainfall are benefit for the initiation of debris flows.