Abstract: In order to diagnose the location and severity of radial friction of centrifugal compressor set in the long-distance gas pipeline accurately, identify causes of radial friction in time, treat the radial friction quickly and properly, and guarantee the safe and stable operation of the long-distance gas pipelines, the mechanism of radial friction was studied. The vibration state of the centrifugal compressor set as a result of fraction faults, such as the local radial friction, local frictional thermal bending and all-round friction was analyzed. Meanwhile, the radial friction of centrifugal compressor set was judged and evaluated according to the abnormal vibration shown by the centrifugal compressor set. Further, it was verified by the fault cases, and the relevant solutions were proposed based on various radial friction types. Conclusively, the research results could provide basis and experience for the identification, analysis, diagnosis, troubleshooting, treatment and overhaul scheme formulation of radial friction fault of centrifugal compressor sets in the long-distance natural gas pipeline, which is helpful to ensure the stable operation of the centrifugal compressor set.