随着区块链技术不断地发展，Fabric框架已成为目前最主流的联盟链框架。面对不同业务需求，区块链研发人员往往为不同的应用场景构建不同的区块链，这种单链架构的业务链面临业务复杂、吞吐率低、拓展难等风险，跨链技术能帮助简单业务链完成互操作从而实现复杂的业务功能。本文综合分析了目前主流跨链技术的优缺点，提出了基于中继链与跨链中间件的跨链模型，并在此模型下基于跨链协议、背书策略交易证明、跨链事务管理实现Fabric跨链智能合约互操作。经过实验与性能分析表明本文提出的方法是可行的。

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.