Abstract: The damage prediction of rock mass under blast loads induced by explosions is essential in rock engineering. Due to the expensive costs of field test measurements, numerical simulation is considered one of the most efficient procedures to predict the response of rock mass under the effect of underground explosion. In this paper finite element technique is used to simulate the dynamic behavior and failure conditions of rock mass subjected to the explosion load. The validation of the finite element model was based on a field experiment conducted in the mountainous regions between Beni-Swef and Elminia, Egypt, [1]. Numerical simulation considered the mechanical properties of rock mass based on the inherent mechanical properties relative to intact rock. Nonlinear three-dimensional numerical simulation of this experimental investigation was carried out using AUTODYN, which is probably the most extensive written code dealing with explosion problems. A comparison between the results determined by the numerical simulation and the field measurements was performed. The simulation results showed a good compatibility with the field measurements.