Consensus methods, systems, and apparatus, including computer programs encoded on computer storage media, are provided. One of the methods is to be implemented on a blockchain maintained by a number (N) of nodes. One of the nodes acts as a primary node and the other (N−1) nodes act as backup nodes. The method includes: detecting a change in a current height H of the blockchain; determining the primary node based on a parameter P and the number of nodes N, wherein the parameter P is proportional to the current height H of the blockchain; in response to determining that the one of the N nodes is the primary node, executing a PBFT normal operation protocol as the primary node; and in response to determining that the one of the N nodes is not the primary node, executing the PBFT normal operation protocol as one of the backup nodes.