Abstract: An improved PBFT mechanism named ISPBFT (Improved Score-Ranked Practical Byzantine Fault Tolerance) is proposed. This mechanism introduced a CART (Classification and Regression Tree) decision tree classification system to periodically classify nodes and assign differentiated consensus permissions based on node categories. The leader selection process was optimized by restricting participation to top-ranked nodes, while simultaneously electing backup leaders to enhance reliability, avoid frequent view switching and reduce communication latency. A dynamic rank-updating mechanism allowed nodes to join/exit flexibly, and the PBFT consensus process was streamlined. Experimental results demonstrate that the new consensus mechanism can effectively reduce communication overhead and improve system efficiency and flexibility.