The Wuxikou hydroproject is located in the middle reach of the Chang River in Jiangxi Province， China. The Wuxikou dam is an important flood control project for the downstream area. Simulation of Wuxikou dam-break flood routing is very important for Jingdezhen flood risk management. In this paper， a two-dimensional dam break flood routing model for the Wuxikou hydroproject is established， based on the shallow water equations by use of the computational code TELEMAC-2D. The downstream reaches are about 62 km length and the reach below the elevation of 60 m is chosen as a research range. The computational range is meshed with triangular elements which are refined locally. The discharge at the dam site and the stage-discharge relation curve are used as the upstream and downstream boundary conditions. The numerical model is verified with field data at the Chang River and Zhangshukeng hydrologic station. Both the simulated values and the meseared values are generally in good agreement, which shows that the TELEMAC-2D model is suitable for dam-break flood routing. The model is applied to simulate the dam-break flood routing under different flood return periods， where dam-break is caused by overtopping flow. The hydraulic characteristic parameters such as depth， discharge and peak flow time, etc. are given by the model, which will be as the basic information for flood risk management mapping and provide the scientific basic for downstream city flood mapping and for downstream city flood control management.