5.12 Wenchuan earthquake triggered a large number of direct and secondary geological disasters, which caused a grave threat on human life and property, as a result of the barrier lake caused by the earthquake is a typical secondary geological disasters. Combination of Dujiangyan City, Baisha River no-man's land of the three barrier lake(Jiadanwan, Yaozigou and Guanmenshan) site engineering geological findings and regional engineering geological conditions, the formation of the barrier lake processes and the status of correlation analysis, its shows that: barrier lake are a result of the earthquake triggered landslides walling up river, due to landslide volume is huge, and quickly dashed from the side to the other side of the valley, creating a high-side and a other low side of barrier lake. And then the seepage stability of barrier lake dam and the slope stability of reservoir banks are analyses, combined with the scene emergency treatment measures of the barrier lake, some recommendations deal with Baisha River no-man's land of the three barrier lake are put forward.
