Abstract: The sharing of medical healthy data is of great significance to the supervision of national medical insurance funds， the settlement of medical disputes and medical research. The medical healthy data sharing platform should ensure the authenticity and privacy of relevant data to avoid data leakage and tampering. At the same time， patients’ ownership of their own medical healthy data should be paid enough attention. This paper designs a medical healthy data sharing system based on Ethereum blockchain， which uses blockchain technology to ensure the transparency and immutability of relevant information. At the same time， IPFS is used to cover the shortage of high storage pressure of blockchain to improve the system performance. For another， CP-ABE encryption and ring signature are used to ensure the security of data and the privacy of user identity information. The test shows that the system provides perfect related functions for different user roles and patients have the control of their own data. In the end， it can provide better data security and user identity information privacy.

Key words: blockchain, IPFS, medical healthy data, attribute-based encryption, ring signature