Abstract: Debris flow has a wide distribution in Chediguangou of Yingxiu-Wenchuan highway, which is 18km away from Yingxiu town. According to investigation, debris flow outbreak in Chendiguangou is more possible and fatal. While it happens, there is a serious threat to nearby highway construction. The tunnel in this section of Yingxiu-Wenchuan highway is adopted. The paper systematically analyzes high and precipitous geomorphology, complex geologic structure, and stratum lithology, and reveals the reasons causing debris flow and hazards zone of construction.