Abstract: In view of wind-diesel-storage microgrid operated in isolated operation mode, a kind of risk evaluation system of islanded microgrid with Load Loss Risk (LLR) indicator and Power Loss Risk (PLR) indicator is proposed to assess the risk level from two aspects of power consumption and power generation. First of all, the models of all components in wind-diesel-storage microgrid are built. Especially the multi-state reliability model of the wind turbine is established based on Markov chain, which reflects the change continuity of the wind speed. Secondly, based on the reliability models of all components of microgrid, the operation state of microgrid is simulated, and its risk level is assessed by using novel risk indicators. In the end, taking the European benchmark low-voltage wind-diesel-storage microgrid as example, the rationality of the proposed indicators are proved, and the effect of different wind speed, failure rate of wind turbine, energy storage capacity and wind power installed capacity on risk level are analyzed. The assessment results can provide reference for capacity allocation, planning and operation of wind-diesel-storage islanded microgrid.