Abstract: Calculation of dam-break water flow is of great significance to the dam-break simulation, break evolution prediction, flood hydrograph prediction, damage assessment, disaster control and people's life and property protection.The calculation methods for common dam-break water flow are studied, such as the average width of dam-break, the maximum flow at tailing dam and the flow graph at tailing dam.Finally, the method is used to forecast the tailing flow in case of a dam break of a tailing reservoir.

Key words: Dam-break water flow, Calculation method, Break