Abstract: Debris flow is one of the common geological disasters in Beijing mountainous area. Through field investigation, experiment and calculation, the formation conditions and development characteristics of Dongtuogu gully are analyzed in detail, and the related movement characteristics are calculated. On this basis, the risk, susceptibility and risk of Dongtuogu gully were evaluated by selecting evaluation factors. The research results are of great significance to the prevention and control of debris flow disaster in Dongtuogu gully.