Abstract: Aiming at the Wenma highway, the hazards of low frequency debris flow on major traffic arteries in southwest mountainous area are analyzed and the corresponding control patterns are put forward. According to the remote sensing interpretation and field investigation, the precipitation, material provenance and terrain data are obtained and the basic parameters of debris flow are analyzed. The results show that the low frequency debris flow may sour and block the highway crossing the debris flow accumulation area, scour and impact the bridge crossing ditches and undercut and erode the tunnels passing by the mountain pass. The corresponding control patterns are as follows: building sufficient-sized drainage canals, grille dam and culvert for the debris flow accumulation area, adopting rubber column protection and constructing diversion dike in front of the piers for the bridge, and constructing check dam in the upper stream and drainage canal in the lower stream for the tunnels. The control model of low frequency debris flow in Wenma highway has certain guiding significance for the construction and operation of the major traffic arteries in southwestern mountainous area of China.