Purpose/Significance Aiming at the difficulty of medical data sharing in traditional medical information systems, an electronic medical record (EMR) security sharing scheme based on blockchain is proposed. Method/Process The blockchain features of decentralization, tamper-proof and traceability are utilized to build a data security sharing platform and establish security mechanisms such as user authentication, medical record encryption, privacy protection and full traceability to realize the safe sharing of EMR. Result/Conclusion The proposed scheme can resist the potential network attack and meet the needs of patients’ privacy protection and confidentiality. The feasibility and operation efficiency of the scheme are verified by experiments.