Abstract: One T3 red copper oil pipe of a power plant fractured after used for half a year. The fracture reasons of the red copper oil pipe were analyzed by methods of macrographic examination, fracture micro analysis, energy spectrum analysis and metallographic examination. The results show that:the fracture type of the oil pipe was stress corrosion cracking; the long-term lubricating oil contained the medium of chlorine and sulfur sensitive to the stress corrosion, and the tensile stress existed in the bending position of the oil pipe, and those factors resulted in the stress corrosion cracking of the red copper oil pipe.