采用包含两个伪态和一个信号态的双伪态协议分析了量子密钥分配系统的性能,比较了双伪态(真空态—弱伪态)和单伪态协议条件下密钥生成率与通信距离的关系,分析了信号态的强度、量子比特误码率、单光子的增益和单光子的误码率对系统密钥生成率的影响,得出密钥生成率的最优化条件,为实现实用安全的量子密钥分配系统奠定理论基础. The performance of quantum key distribution system is analyzed by using the dual pseudo-state protocol with two pseudo-states and one signal state. The key generation rate and the rate of key generation are compared between the two pseudo-states (vacuum state-weak pseudo- state) The relationship between signal strength, quantum bit error rate, single-photon gain and single-photon bit error rate is analyzed. The optimal conditions of key generation rate are obtained as To achieve practical security quantum key distribution system laid the theoretical foundation.