Abstract: A compressor spindle fractured transversely in daily work, and means such as chemical compositions analysis, mechanical properties test, metallographic examination and fracture morphology observation were used to determine the fracture causes. The results show that the fracture of the spindle was rotating bending fatigue fracture, and the fracture initiated from the intergranular cracks at the surface repair welding heat affected zone. So the improper repair welding was the main cause for the fracture failure.