Observer-based consensus control problem for multi-Autonomous Surface Vehicle (ASV) systems under denial-of-service (DoS) attacks is investigated in this paper. To mitigate the impact of DoS attacks on the consensus of ASV systems, a distributed switching observer is introduced, which is capable of freely switching its states to observe the leader’s state information. Employing the adaptive backstepping approach and utilizing the observer’s estimated values, a distributed controller is designed for each ASV. Consensus among the ASVs is then rigorously proven via Lyapunov stability analysis. Finally, the effectiveness of the proposed control strategy is validated through numerical simulations.