Abstract: An accident occurred in an enterprise in which the connecting rod cap and its fastening bolts of a glycol gas recycling reciprocating compressor fractured. A series of study on the fractured connecting rod cap and fastening bolts were carried out by visual inspection, material chemical composition analysis, SEM observation and metallographic examination. The results show that the main reason of the compressor accident could be described as following: a gap between two connecting rods generated because the compressor connecting rod bolts were not fully tightened; then the crack source was induced by fretting wear at the surface of bolts, and then the crack grew to contribute to fatigue fracture; at last the connecting rod cap fractured and led to the deformation of the connecting rod.