The alliance chain system is a distributed ledger system based on blockchain technology, which can realize data sharing and collaboration among multiple parties while ensuring data security and reliability. The Practical Byzantine Fault Tolerance (PBFT) consensus algorithm is the most popular consensus protocol in the alliance chain, but the algorithm has problems such as high complexity and too simple election of the master node, which will make PBFT unable to be applied in scenarios with too many nodes. At the same time, there are certain security issues. In order to solve these problems, this paper proposes an improved Byzantine consensus algorithm, Polymerization Signature and Reputation Value PBFT (P-V PBFT). Firstly, the consistency protocol process is improved based on the aggregate signature technology. The simulation results show that the P-V PBFT algorithm can effectively reduce the overhead of network transmission, and the time complexity of the algorithm decreases exponentially, which improves the efficiency of the consensus process. Secondly, the node reputation election mechanism is introduced to elect the primary node, and the security analysis is carried out to verify the fairness and security of the primary node election of the P-V PBFT algorithm. Therefore, as a feasible improvement of the blockchain consensus protocol, the P-V PBFT algorithm can provide more efficient and secure guarantee for the blockchain system in practical application.