The popularity of cloud accounting is due to its low cost of entry, efficient data processing, and high business efficiency. However, security issues in cloud storage can affect user trust in the service. To address these security issues, a blockchain-based encryption technology model for cloud accounting data security is proposed. Firstly, the feasibility of integrating blockchain technology and cloud accounting is analyzed. Then, an elliptic curve cryptography-based cloud accounting data security solution is proposed. Blockchain and evidence chain technology are used to ensure data security and support data privacy protection for cloud service providers and third-party auditors. The proposed solution has a small computational overhead, as it does not require exponentiation or bilinear pairing. Experimental results show the proposed solution can enhance user control over cloud accounting data, ensure data transmission security, and improve trust between users and cloud accounting service providers. Moreover, it is more efficient.