Abstract: Disclosed are a consensus method and device, and a blockchain system. A primary node directly broadcasts a transaction hash list including a hash value of at least one unverified transaction in the system, so that a backup node and the primary node simultaneously verify the at least one unverified transaction, and the backup node stores a first verification result obtained by verification and a first hash value of the at least one unverified transaction. The primary node broadcasts an obtained second verification result and a second hash value of the at least one unverified transaction in a pre-preparation message after completing the verification, so that the backup node searches for the first verification result based on the second hash value, and broadcast a preparation message when the second verification result is the same as the searched first verification result, to enter a subsequent consensus stage, and complete the consensus processing.