A method includes the steps of: monitoring status information of a blockchain system; determining whether the status information meets a blockchain branch condition; when the status information matches the blockchain branch condition, writing a branch instruction to a selected block of the blockchain, wherein the branch instruction is configured to enable the blockchain to form a plurality of branches, and divide a plurality of blockchain devices in the blockchain system into a plurality of groups to verify the branches in parallel; and obtaining a maximum transmission delay time in the group, and deciding a new one to generate blocks of the first branch according to the maximum transmission delay time.