Abstract: In recent years, the Internet of Drones (IoD) technology has been widely deployed in logistics, agriculture, aerial photography, disaster rescue, and other fields. However, the inherent dynamics and openness of IoD introduce numerous security challenges: as the drone fleet scales up, the computational overhead of traditional one-to-one authentication mechanisms increases sharply; meanwhile, communication among drones relies on open channels, rendering them vulnerable to security threats such as unauthorized access and data interception. To address these issues, this paper proposes a lightweight batch authentication key agreement protocol for IoD environments. The protocol supports batch identity authentication and key agreement. Compared with five existing protocols, it demonstrates significantly lower computational overhead and achieves at least a 50% reduction in communication overhead when negotiating 30 session keys. Formal security analysis is conducted using the widely adopted random oracle model and ProVerif tool. The results demonstrate that the protocol satisfies the security requirements of IoD environments and effectively resists typical attacks, including impersonation attacks, replay attacks, man-in-the-middle attacks, and known session key attacks. Moreover, it enhances authentication efficiency while notably improving security and functional completeness.