二端口网络的４个电压、电流之间的关系，可用６种不同参数描述，而每种参数又有４个元素。对于线性非时变的无源二端口网络，在零初始条件下，若存在互易性及对称性，则其电路参数具有一定的特殊性。本文将对这些特征进行详尽的分析和讨论，并由定义给出简化后的参数计算方法。 The relationship between the four voltages and currents in a two-port network can be described by six different parameters, and each parameter has another four elements. For a linear time-invariant passive two-port network, the circuit parameters have some particularities under the condition of zero initiality if reciprocity and symmetry exist. In this paper, these features will be analyzed and discussed in detail, and the simplified calculation method will be given.