The giant debris flow and flush flood that burst within Sanyanyu and Luojiayu gullies in the north side of Zhouqu County in August 8,2010caused tremendous losses of the local people′s lives and properties.Based on field investigation and survey,important roles of blocking projects in the treatment of SanyanyuGully were expatiated and the view of dominated blocking projects in combination with drainage projects wasproposed in terms of the analyses of geo-environmental conditions,formation and movement characteristics of the debris flow,storage and supply modes of loose materials,erosion and deposition in gully and disasterprevention of the county town,etc.To ensure enough storage capacity of sand hindrance and safe reliability,various types of blocking dams were analyzed and medium or high dams with high-impact strength werechosen to control debris flow disaster.According to the characteristics of supply and activity of debris flow inevery gully section,forms,types and functions of the blocking dams were analyzed,and blocking projectswere deployed systematically.