The Practical Byzantine Fault Tolerance protocol (PBFT) has been widely deployed in the blockchain network. However, two main issues, the communication complexity and the inability of nodes to join/exit the network without restarting the system, significantly degrade consensus efficiency. To solve these problems, we propose a novel dynamic practical byzantine fault tolerance protocol based on node grouping (NG-PBFT), which is realized by grouping nodes into consensus and observation groups. The nodes in observation group preprocess nodes’ joining/exiting requests, while the nodes in consensus group reach con sensus about the preprocessed results. Furthermore, an adaptive three phases or two phases consensus mechanism that can effectively improve consensus efficiency is proposed. We provide theoretical complexity to show that our protocol reduces the communication complexity of con sensus and improves consensus efficiency significantly.