Abstract: Identity authentication protocols serve as a critical component in the security architecture of vehicular ad hoc networks（VANETs）. However, the majority of existing authentication protocols have overlooked the security challenges posed by frequent vehicle handovers across different roadside units（RSUs）. To address these issues, this paper proposes a vehicle-to-roadside batch handover authentication protocol based on the Chinese Remainder Theorem. The proposed protocol leverages elliptic curve cryptography to establish a certificateless anonymous authentication mechanism, enabling lightweight mutual authentication between vehicles and roadside units. Additionally, the Chinese Remainder Theorem is used to distribute handover authentication credentials, and the switching process is optimized through pre-batch authentication, thereby enhancing overall authentication efficiency. The security of the proposed protocol is formally analyzed within the random oracle model and further validated through comprehensive informal security assessments. Performance comparison with existing protocols demonstrates that the proposed protocol effectively reduces both computational and communication overhead.