Abstract: Given that the conventional blockchain model for the fruit and vegetable supply chain has the problems of insufficient depth of traceability information, insufficient data correlation, and low query efficiency, a graph blockchain model was proposed in this study. Firstly, the graph theory was used to improve the block data structure of the traditional blockchain and change the storage structure of the sequence table in the traditional blockchain structure into a graph structure that can facilitate the storage of in-depth traceability information for associated storage of deep traceability information. Then, the mapping relationship between physical block data and graph block chain model was established through a graph block chain mapping model, and according to the logical structure of the fruit and vegetable supply chain, the graph block data structure was established. Customized design of smart contracts for graph blockchain data storage, query and authority management was performed to ensure the reliability of supply chain data. Finally, the graph blockchain model was developed based on the XuperChain platform and its performance was experimentally compared with that of the traditional blockchain. The results showed that the graph blockchain allows deep traceability of the fruit and vegetable supply chain and greatly improves the efficiency of data query, which can provide a new method and idea for the traceability information storage and fast query of the fruit and vegetable supply chain based on blockchain.

Key words: fruit and vegetable supply chain; graph blockchain model; graph structure; in-depth traceability; smart?contract