从变截面杆作一维纵振动的运动方程出发，建立了机械四端网络的数学模型及传输特性方程，给出了几种常用变截面杆的四端网络传输参数。分析了超声换能器和变幅杆的频率方程及两端振速比，计算了超声手术刀振动系统的振型及应力分布。四端网络设计方法可有效地设计各种换能器。变幅杆以及由它们组合的复杂振动系统。 Based on the one-dimensional longitudinal vibration equation of variable cross-section bar, the mathematical model and transmission characteristic equation of the four-end network are established, and the four-terminal network transmission parameters are given. The frequency equation of ultrasonic transducer and horn and the vibration velocity at both ends were analyzed, and the mode shapes and stress distribution of ultrasonic scalpel vibration system were calculated. The four-terminal network design method can effectively design a variety of transducers. Horn and complex vibration system combined by them.