Aiming at the failure of turbo-compressors with relatively high technological maturity, the leakage positions is analyzed by the optical microscope, scanning electron microscope, energy dispersive spectrometer and vickers micro-hardness tester. It is determined that the failure site is the compressor lead copper tube. The failure mechanism of the copper tube leakage is fatigue failure. The cause of the leakage failure is that the compressor lead copper tube material is too hard, which is not suitable for re-machining and the mechanical processing technology is not compatible with the hardness of the copper tube.