This thesis briefly introduces the emergency handling of Tangjiashan barrier lake. Combined with practice, it concludes the rapid capture and application technique of the relative landform, geologic and water information for barrier lake. From the form condition and process, the form mechanism of barrier dam is analysed analyzes.The security of barrier dam is evaluated and analyzed, and the flood propagation after the dam break is calculated. Finally, the emergency handling scheme, digging channel and draining scheme and the handling effects are briefly introduced.