充分利用柴油机缸盖和喷油器、气门摇臂座、螺栓等部件的振动信号，对柴油机的工作过程、喷油系统和气门机构等进行故障诊断有着重要意义。文中着重分析柴油机缸盖振动信号的时间特征和循环波动性，并提出消除波动性的一些措施，提高了故障诊断的准确性。 Make full use of diesel engine cylinder head and injector, valve rocker seat, bolts and other components of the vibration signal on the diesel engine working process, fuel injection system and valve mechanism for fault diagnosis is of great significance. In this paper, the time characteristics and cyclic fluctuation of diesel engine cylinder head vibration signals are analyzed emphatically. Some measures to eliminate the fluctuation are put forward to improve the accuracy of fault diagnosis.