The capability and capability of discrete fracture networks for simulating rock mass fractures has been proven. In most of the modeling conducted, the average value for the friction angle of each fracture group is considered. While in nature, each fracture group has its own distribution function for this fracture mechanical parameter. Along with the geometric parameters of the fracture network, the heterogeneous nature of the fracture mechanical parameters is very important for understanding the behavior of the rock mass. In this research, the effect of the statistical distribution of the friction angle of fractures on the strength of the rock mass has been studied using the discrete fracture network approach in the UDEC discrete component software. For this purpose, first, a discrete fracture network has been coded and a normal distribution function has been considered for the friction angle of each fracture group. Then, four fracture network groups with different fracture intensities have been generated and 5 repetitions with standard deviations of 2.5, 5, 7.5 and 10 degrees have been considered for each group. Finally, the results have been compared and examined with the base case, i.e. using the average value. The results of numerical analyses indicate the importance and significant impact of considering the statistically distributed effect of the mechanical parameter of friction angle in a discrete fracture network on the strength of the rock mass.