Abstract: When disaster-induced emergencies occur in distribution systems (DSs), distributed generators are used to form islanded microgrids (MGs) and ensure the constant power supply to critical loads, which is essential to reducing outage losses and enhancing system resilience. Traditional resilient DS dispatching approaches concentrate on static security constraints prior to and after the emergencies, but ignore the dynamic frequency characteristics during the islanding transition, thus failing to ensure the successful MG formation. This paper proposes a prevention and emergency coordinated DS dispatching method that considers dynamic frequency stability during the MG formation process. A stochastic DS dispatching model is formulated, with the objective of minimizing the total operating costs. Based on the preventive scheduling and the post-disaster partition schemes, the power imbalance during MG formation process is quantified. Frequency stability constraints are developed based on a time-dependent discretized frequency response model. Furthermore, nonlinear constraints are linearized, and the origin model is transformed to a mixed integer linear programming problem to facilitate its solution. The modified IEEE-37 node test distribution system is used to validate the effectiveness and superiority of the proposed method.