A data backup method includes querying a first block of a first blockchain for unused transaction output information based on a first condition being met, the first block including each block of all blocks included in the first blockchain; generating transaction information according to the unused transaction output information obtained based on the querying, the transaction information indicating a transaction operation based on an account address to which the unused transaction output information belongs; recording the transaction information in a second block and releasing the second block, and recording the second block on which a consensus is reached on a second blockchain; and backing up the first blockchain into a storage system, and deleting the first blockchain. Counterpart apparatus, terminal, server, and/or non-transitory computer-readable medium are also contemplated.