In this paper,the health status of the diesel engine was defined.The performance degradation process of diesel engine caused by wear is divided into two categories.The bench test of the diesel engine was carried out to monitor the wear state of these two kinds of the degradation process.The on-line visual Ferrograph(OLVF)monitoring data and performance monitoring data were all acquired for diesel engine health condition evaluation.Test results show that: the OLVF shows more sensitivity than other performance monitoring sensor.Whereas,comprehensive utilization of both kind of information can further improve the accuracy and efficiency of diesel engine health condition monitoring.