Abstract: The leakage of a heat exchanger was analyzed by macroscopic observation, chemical composition analysis, scanning electron microscopy and energy spectrum analysis, X-ray diffraction analysis, metallographic examination and other methods. The results show that the chlorosilane medium in the tube side or shell side of the heat exchanger was hydrolyzed to form corrosive chloride ions, which led to stress corrosion cracking on the inner wall of the shell and in the pipeline under the combined action of corrosive medium, working stress and welding residual stress, and finally caused pipeline leakage.