Data sharing is a powerful way to break the "Data Isolation" dilemma in the era of Big Data and how to ensure the safe sharing of data is the main problem that we face at present. Therefore, in this study, we propose a DOB framework by using Blockchain technology and ciphertext-policy attribute-based encryption. The system public key, user's attribute, ciphertext, and user secret key of the CP-ABE are stored in the Blockchain database through the smart contract and serialization method, and the access authority of the database and the registration authentication dataset are deployed to implement fine-grained sharing of data. The experimental results show that compared with the Timely CP-ABE with Blockchain scheme by Jemel et al, the proposed framework further improves the security of data sharing.