活塞环是柴油机的关键部件之一 ,如果出现故障将严重影响柴油机的性能 .文中介绍了时频分析理论 ,利用时频分析方法对柴油机正常和活塞环故障状态下的机体表面振动信号进行了分析 ,提取了特征信息 ,两种状态下结果区别明显 ,说明时频分析方法能够作为柴油机的故障诊断和状态监测的有效工具和方法 Piston ring is one of the key components of diesel engine, if it fails, it will seriously affect the performance of diesel engine.This paper introduces the theory of time-frequency analysis, using the time-frequency analysis of the normal and piston ring failure of the body surface vibration signal analysis , The characteristic information is extracted, the difference between the two states is obvious, which shows that the time-frequency analysis method can be used as an effective tool and method for fault diagnosis and condition monitoring of diesel engine