With the rapid development of the logistics industry, the problem of product information traceability in the supply chain is becoming more and more serious. However, the traditional product traceability system has some shortcomings, such as the vulnerability of centralized database, the inability to avoid tampering, and the difficulty in accountability and positioning. The decentralized, traceable and tamper-proof features of blockchain can improve the existing supply chain and solve the above problems. This paper firstly analyzed the information exchange of products in the supply chain, and then proposed the product information tracing scheme combining block chain, in which the improved DH key exchange algorithm and RC4 encryption algorithm were used to encrypt the product information to improve the security of the information.