With the continuous development of blockchain technology,Fabric framework has become the most mainstream consortium blockchain framework.Faced with different business requirements,blockchain developers often build different blockchains for different application scenarios.This single-chain business chain faces risks such as complex business,low throughput and difficult expansion.Cross-chain technology can help simple business chains to interoperate and realize complex business functions.In this paper,the advantages and disadvantages of the current mainstream cross-chain technologies are comprehensively analyzed,and a cross-chain model based on relay chain and cross-chain middleware is proposed.Under this model,Fabric cross-chain smart contract interoperability is realized based on cross-chain protocol,endorsement policies transaction proof and cross-chain transaction management.Experiments and performance analysis show that the method proposed in this paper is feasible.