In order to solve the problem of voltage sag and short-term voltage interruption of sensitive load, an active fast switching method for active distribution network is proposed in this paper. First, the fast detection method of voltage sag and short-time voltage interruption is studied. Then, the structure and principle of fast switch based on eddy current driving are studied. The fast switch is used in the main power supply line breaker and the bus connection breaker, which can quickly switch the power-lost load to the backup power supply, greatly improving the switching speed. At the same time, the distributed power supply in active distribution network is used to support the bus residual voltage in the switching process, minimizing the impact of the voltage drop on the sensitive load as much as possible. The results of dynamic simulation test verify the superiority of the proposed active fast switching scheme.