The microgrid is the crucial technology that brings the comprehensive efficiency of various distributed generators into full play，the reliability study of which having played a basic role in its application. Meanwhile，reliability indices are prerequisite for microgrid reliability evaluation.By analyzing the reliability requirements of the microgrid，it is found that there are limitations in merely applying the reliability indices of the distribution system to evaluate microgrid reliability.It is necessary to put forward a new set of specific and feasible indices for microgrid reliability evaluation.For this reason，microgrid reliability indices for four main aspects are presented，namely，the equivalent features of microgrid，the characteristics of intermittent power source，the islanding state of microgrid，and the benefits of microgrid.Meanwhile，a series of definitions and formulas for calculating the indices is proposed，and their meanings are discussed.Numerical results of the case demonstrate that the proposed indices can reflect the effect of power source configuration，operation state，and renewable energy application on microgrid reliability.Finally，useful investigation on establishing the microgrid reliability index system is made.