A 2D numerical model based on Boltzmann equation and an unstructured FVM grid with a kinetic flux vector splitting (KFVS) scheme is developed to simulate dam-break wave. Taking one reservoir dam at Yuhang District of Hangzhou as an example， the propagation of the dam-break wave of the reservoir dam is simulated by this model. The simulated results show that the influence region given by dam flood is very large at the downstream of the dam: about 11 km away from the dam， the depth of the water can still reach more than 8:5 m. The life loss caused by dam failure is evaluated. Using regional population， and geography data as main input， it is then integrated with the dam-break flood routing model to acquire the hydraulic parameters， including depth and velocity， and then to estimate the life loss. The analyse results show that total life loss number is up to 712. This number is close to the conclusion of some existing researches. This method can be applied to other reservoirs after making some modifications， so as to provide technical support for decision makers.