针对求解传输线上任意一点电压与电流的复杂的计算量问题,本文提出了电压圆图概念和电流圆图概念。借助两种圆图将直观、方便的求出传输线上任意一点的电压与电流,计算量大为下降。两种圆图理论的建立基于经典传输线理论模型。在推导出传输线上任意一点电压与电流的计算方程之后,利用Z平面与时域角度之间的关系,导出了电压与电流在Z平面的方程,进一步借助Z平面的实轴和虚轴最终构建了电压圆图与电流圆图。 In order to solve the complicated calculation problem of voltage and current at any point on transmission line, this paper presents the concept of voltage circle graph and current circle graph. With the help of two kinds of circular diagrams, the voltage and current at any point on the transmission line will be intuitively and conveniently calculated, greatly reducing the amount of calculation. The establishment of two kinds of circular graph theory is based on the classical transmission line theory model. After deducing the calculation equations of voltage and current at any point on the transmission line, the equations of voltage and current in the Z-plane are deduced by using the relationship between the Z plane and the time domain angle. Finally, the real and imaginary axes of the Z plane are finally constructed The voltage circle chart and the current circle chart.