The high communication complexity of Practical Byzantine Fault Tolerance （PBFT） consensus protocol will lead to low consensus efficiency， the failure or the existing of Byzantine behavior of the single primary node will lead to the stop of consensus process. In order to solve these problems， an Improved Multi-primary-node Practical Byzantine Fault Tolerance （IMPBFT） consensus mechanism was proposed. Firstly， the number of effective consensus rounds of nodes was calculated by the number of consensus rounds of nodes， the number of consensus rounds with Byzantine behavior and the priority values assigned to the nodes， and several primary nodes were selected according to the size of effective consensus rounds. Then， the original consensus mechanism was improved to make all nodes use the improved consensus mechanism for consensus. Finally， pipeline was introduced to implement the concurrent execution of IMPBFT consensus. In the pipeline operation， multi-stage messages of different rounds’ consensus were signed together， and no fixed cycle was used to control the pipeline. Theoretical research and experimental results show that， the multi-primary-node structure of IMPBFT is more secure and stable than the consensus structure of single primary node. Compared with PBFT and Credit-Delegated Byzantine Fault Tolerance （CDBFT） consensus with square level traffic， the proposed IMPBFT reduces the traffic to linear level. The IMPBFT has better performance than PBFT and CDBFT in terms of transaction throughput， scalability and transaction delay. The IMPBFT using the “multi-stage messages signed together with no fixed cycle” pipeline has improved the transaction throughput by 75.2% compared with the IMPBFT without pipeline.