ABSTRACTElectrical percolation of carbon black (CB) and carbon nanotubes (CNTs) filled into silicone rubber (SR) is analyzed by the three‐dimensional (3D) Monte Carlo simulation. First, the 3D models and simulation parameters of CB and CNTs are researched to narrow the deviation between simulation and experimental results of CB/SR and CNTs/SR. The degree of agglomeration is the most important parameter in simulation for CB. The 3D model of CNTs is the most important factor in simulation for CNTs. Then, the 3D Monte Carlo simulation for CB/CNTs/SR is developed based on the optimized 3D models and parameters of CB and CNTs. The results yielded by the simulation with optimized parameters are similar to the experiments and synergistic conductive effect of two hybrid fillers in nanocomposites exists. This work has demonstrated that the quantification of the electrical percolation of two hybrid fillers in nanocomposites by Monte Carlo simulation is feasible. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48222.