In medical referrals, it is critical to securely and efficiently share Electronic Medical Records (EMRs) for timely and accurate treatments. The decentralization and tamper-proof of blockchain provides new options for secure sharing of diagnosis and treatment data. In this paper, we propose a modular sharing scheme for EMRs using consortium blockchain and proxy re-encryption. Specifically, to meet security and privacy requirements of medical referrals under the healthcare consortium model, cloud servers are employed to store the encrypted EMRs. Additionally, modular encryption is designed to realize fine-grained access control. In our scheme, consortium blockchain is employed to store patients’ index key group, and it is responsible for performing proxy re-encryption operations. Such design ensures secure access control of patients’ EMRs, and doctors within the medical consortium model can access and/or update EMRs after obtaining authorization from patients. We analyse the security and performance of our scheme, and compare it with a few relevant schemes. According to the comparisons, our scheme has more functionalities, and it achieves fine-grained access control of patients’ EMRs. Moreover, resource consumptions of patients and doctors are light. Specifically, time cost of our scheme is reduced at least 25 \(\%\) .