目前国内外应用单通道信号或同一截面相互垂直双通道信息融合监测转子系统振动幅度的方法，漏报警率很高。文中探讨将模态分析和频谱分析理论结合，应用转子两个截面四个探头信息监测转子振动幅度。论述了转子自由振动、强迫振动和瞬态振动时转子振动监测参数的计算原理。以滑动轴承支承的单盘偏置转子系统为例，阐述了本原理的应用。 At present, the method of monitoring the vibration amplitude of the rotor system using single-channel signals or vertical-channel two-channel information fusion with the same cross section at home and abroad has a high missing alarm rate. In this paper, modal analysis and spectrum analysis theory are discussed. The rotor vibration amplitude is monitored by using four probe information of two sections of the rotor. The calculation principle of the rotor vibration monitoring parameters when the rotor free vibration, forced vibration and transient vibration are discussed. Taking a single disc-biased rotor system supported by plain bearings as an example, the application of this principle is illustrated.