Abstract: Power supply reliability indices of islanded microgrids indicate the ability of providing continuous power supply for the user. When reliability indices are known, the reliability of islanded microgrid can be assessed. In order to analyze the influence of different control modes on the reliability, three kinds of control modes are made. And the time series model of wind-solar power and the two pool model (Kinetic Battery Model, KiBaM) of battery are established. The effect of component failure on the operation state of a microgrid and the load shedding method based on the location and the importance are analyzed. The sequential Monte Carlo simulation method is used to sample the state of components, and then to determine fault component. By comprehensively considering such factors as the stochastic output characteristic of power, control methods, the component failure, the load shedding method and the grid structure, a power supply reliability evaluation algorithm of islanded microgrid is proposed. In the end, taking a microgrid with simple structure as an example, the power supply reliability evaluation is carried out, and the correctness of the proposed algorithm is verified by example results.