Abstract: With the increasing level of agricultural informatization, modernization and intelligence, different agricultural production regions need to develop regional agricultural information network security according to the actual situation to ensure the integrity and privacy of agricultural data. The security of data sampled by Internet of Things（IoT） devices in agriculture is very important because any malicious tampering or destruction may lead to wrong decisions and cause incalculable losses. To address the above issues, this study designs a dual blockchain solution based on IPFS storage for the protection of agricultural sampling data security in IoT networks, where the system can retrieve complete data segments through a prophecy machine mechanism, and designs an Ethereum technology-based blockchain-agricultural sample data chain（ASDC） based on Ether technology and improves the account of each type of sampled data in Merkle Patricia Trie（MPT）. After the data is stored as blocks in ASDC, a block hash is generated and uploaded to the Ethernet master chain to maintain a public record in case of malicious attacks. The results of testing the system show that the method has less time consumption than cloud storage and blockchain-only storage, and also meets the requirements of cybersecurity.