To solve the security problems caused by the disclosure of blockchain ledgers， the key lies in the hiding of private information. An attribute-based encryption scheme with multiple authorities was proposed for privacy protection of blockchain data. Compared to single authority， multiple authorities are decentralized and avoid any single point of failure. First， the key component generation algorithm was modified， where each authority used the user identity as a parameter to generate private key components， preventing collusion between nodes to access unauthorized data. Then， identity-based signature technology was modified to establish a connection between user identities and wallet addresses， making the blockchain policeable and the illegal users traceable. Finally， based on the DBDH （Decisional Bilinear Diffie-Hellman） hypothesis， the safety of the proposed scheme was proved in random oracle model. The experimental results show that， compared with the blockchain privacy protection scheme based on the ring signature based on the elliptic curve and the blockchain privacy protection scheme supporting keyword forgetting search， the proposed scheme takes the least amount of time and is more feasible， when generating the same number of blocks.