Practical Byzantine Fault Tolerance (PBFT) algorithms are renowned for their exceptional liveness, security, and fault tolerance. They possess significant value, especially within the domain of blockchain, with particular relevance to consortium chains. However, the current PBFT algorithms suffer from structural imperfections and high communication overhead. To address these issues, we propose a credit grouping PBFT algorithm based on n-ary tree communication topology (TCG-PBFT). Firstly, we propose a novel credit evaluation method to better align with the credit grouping approach employed in this study. Secondly, we rearrange the nodes, categorizing them into three groups based on credit scores: the primary node group, the consensus node group, and the observer group. Additionally, we employ a consistent hashing algorithm for the random selection of the primary node, replacing the previous method of entirely random selection across the network. Lastly, we enhance the message dissemination method in the consensus process by integrating credit grouping with a tree-structured mechanism, thus utilizing a tree-structured approach for message transmission instead of the original single-point broadcasting. Experimental results have shown that, compared to existing methods, the consensus algorithm structure proposed in this paper significantly mitigates the decline in throughput and the increase in latency as the number of nodes increases.