Quantum communication is one of the most important branches of quantum information, which is the combination of quantum mechanics and information theory. The security of B92 quantum key distribution protocol was analyzed in the non-ideal circumstances. A new quantum circuit model of B92 quantum key distribution protocol was raised to design simulation models under different noise channel models using the QCircuit. Two indicators of BER and rsec were introduced, and then the circuit models were designed to simulate and analyze the effectiveness and security of B92 key distribution protocol under different noise channel models. The experimental results show the new circuit design achieves the purpose of B92 key distribution protocol and the design approach is more universal significant. It can be used to construct more quantum simulation models of different quantum key distribution protocols.