Abstract: Aiming at the issues of low authentication efficiency and poor scalability in traditional ID authentication schemes based on digital certificates, this paper proposes a certificate-free distributed anonymous authentication scheme based on the unspent transaction output (UTXO) model. Users upload traffic messages to the Regional Trusted Authority (RTA) together with transactions generated based on the UTXO model. The RTA verifies the legitimacy of the message sender’s identity by checking the validity of the transaction input contained in the uploaded transaction. In addition, this paper designs a transaction update mechanism to guarantee the scheme scalability, avoiding a continuous increase in the system database storage caused by maintaining digital certificates. Based on the security analysis, compared with the existing identity authentication schemes in vehicular ad-hoc network (VANET), the proposed scheme is better in terms of security considerations such as anonymity, traceability and authentication. The theoretical analysis and the simulation experiments show that computational and storage costs of the proposed scheme are lower than those of the existing common authentication schemes. In terms of scheme scalability, the retrieval overhead of the blockchain state database based on the simulation environment remains at around 0.3 ms, while the storage cost is stable at around 33 M. In terms of authentication efficiency, the proposed scheme outperforms the existing schemes by at least 33.19%.