The aim of this paper is to propose the impact failure analysis of reinforced concrete beam using tensile softening technique based on the damage mechanics. In general, tensile crack is the most dominant factor for concrete and it is not appropriate to evaluate their effect by theory of plasticity. Thus mechanical failure of concrete is considered by not only conventional plastic theory but also damage mechanics. In the analysis to calculate the plastic deformation, Drucker-Prager yield surface model is employed, on the other hand Von-Mises yield surface model is applied for the reinforcing bar. Besides, mechanical influence of tensile crack in the concrete is also considered as the decrease of effective cross-section area using anisotropic damage variable. Several impact tests of RC beam are reviewed and their impact response are simulated by proposed analysis method. As a result, it is confirmed that proposed method can simulate impact response of RC beam and it could predict precise failure condition such as the distribution of concrete crack using anisotropic damage model.