Aiming to address issues of query request submission, data transmission leakage, and vehicle privacy leakage caused by untrustworthy cooperating Partners (CPs) in privacy-preserving caching for Internet of Vehicles (IoV), this paper proposes a trust mechanism privacy protection scheme combining blockchain and multi-party evaluation (TMPP-BMPE). First, a data broadcasting mechanism is proposed based on the Paillier encryption algorithm and the Elliptic Curve Digital Signature Algorithm (ECDSA) for data protection. The homomorphic encryption algorithm and the ECDSA are applied for data privacy protection during transmission. Second, a trust mechanism based on multi-party assessment is proposed. The trustworthiness of CPs is comprehensively assessed considering assessment indicators from multiple entities, mitigating risks of interacting with untrustworthy CPs. Finally, a blockchain-assisted trust management scheme is designed to effectively prevent malicious tampering with trusted data. The simulation experiment results show that the TMPP-BMPE performs well in protecting data privacy, evaluating the trustworthiness of CPs, and preventing data tampering. It provides valuable insights for security and trust establishment in IoV.