The Qingling Ditch is located in Five Community of Nianzi Village, Qingchuan County of Sichuan Province, where there are complex geological conditions. After “5·12” earthquake, a large number of Collapse rockfalls and loose solid substances appeared in the trench, which provides a sufficient source for the break-out of debris flow. Continuous heavy rainfalls occurred in Qingling ditch region in August 2008. Then, the debris flow break out in Qingling ditch on August 25. At the origin of the Qingling Ditch and both sides of the trench, there developed a large potential unstable slope, three large-scale dangerous rockmass, and one which formed in the “5·12” earthquake collapse deposits at present. Through the field investigation, laboratory tests and dynamics character analysis, the authors propose a comprehensive management including UX-150 type debris flow fence, dam, drainage trough and culvert reconstruction.