Abstract: The coordinated control of each micro source in the isolated microgrid relies heavily on a safe and reliable cyber system. Random failure of cyber elements will affect the microgrid reliability because of the control functions failure. This paper proposes an isolated microgrid reliability modeling and evaluation method considering frequency control. Firstly, the cyber physical fault coupling relationship is established according to the centralized frequency control method and the influence of cyber elements’ failure on frequency control mode. Secondly, a quantitative evaluation method for the fault consequences is put forward based on the isolated microgrid frequency modulation model. Then a set of new microgrid reliability indices is defined to characterize the impact of control failure on system reliability. The reliability of isolated microgrid cyber physical system is evaluated by sequential Monte Carlo method based on frequency control simulation. The example analyzes the influence of cyber elements failure through the frequency control process on the reliability of isolated microgrid. The indices, models and methods proposed in this paper are verified by the simulation result, which can provide effective technical support for the planning and operation of isolated microgrids.