<p>False data injection attack (FDIA) is one of the critical risks threatening the safe operation of islanded Microgrids (MGs). To address this issue, this paper proposes a dynamic event-triggered adaptive sliding mode (ETASM) secondary control strategy, aiming to accurately restore the system frequency and voltage to their reference values. In the considered scenario, FDIA depends on the system’s frequency and voltage states, with the upper bound of the attack signal being unknown. By integrating adaptive sliding mode control, the proposed strategy can estimate the upper bound of the attack and thereby effectively mitigate the interference of FDIA on the system. Additionally, through the integration of a dynamic event-triggered mechanism, the strategy significantly reduces the system’s communication overhead while ensuring the achievement of secondary control objectives. Finally, simulation results demonstrate that the proposed strategy exhibits effectiveness and superiority: it not only guarantees the security and stability of the system but also improves the utilization efficiency of the communication network.</p>