WenChuan Earthquake brought out large-scale and group-occurring secondary mountain hazards. They not only severely destroyed the highways and blocked the traffic, but also blocked the process of earthquake relief and reconstruction. After the remote sensing monitoring and field survey in XuanKou-Yanmen part of the DuJiangyan-WenChuan Highway, the article describes the type and the distribution of the secondary mountain hazards and analyzes the damage of the subgrades, pavements, bridges and tunnels along the DuJiangyan-WenChuan Highway. In addition, combining with the temporal characteristics of secondary mountain hazards, the article puts the countermeasure and suggestion of the relief and reconstruction of the traffic system. The research result shows that: (1)In the research region, strong earthquake causes a lot of secondary mountain hazards such as collapses, landslides, debris flows, dammed lakes. There are 3863 collapses with a total area of 68.9km2, 74 debris flow gullies, 18 landslides, 5 dammed lakes, 5 ground fissures which is longer than 1km.((2)Earthquake and secondary mountain hazards severely destroyed the highway and traffic. From XuanKou to YanMen in WenChuan, there are 299 blocks in DuJiangyan-WenChuan Highway. Also, there are barriers with a length of 23.814km. 80% of the highway, including 87 bridges and 10 tunnels, has been destroyed. (3)The distribution of the main kind of collapse, landslide, debris flow, dammed lake mainly depends on seismic intensity, geological structure, topography and geomorphology and rock characters.4) By using the technology of GIS and remote sensing, the disaster evaluation and dynamic monitoring can be effectively carried out, so it can provide the scientific basis and references to the relief and reconstruction.
