Abstract: Based on a failure case of high-pressure heat-exchanger pipe of a diesel hydrogenation unit, the reasons for stress corrosion cracking of austenitic stainless steel equipment were analyzed, as well as the stress corrosion process of stainless steel equipment. In addition, the factors affecting the polythionic acid stress corrosion cracking of stainless steel equipment were analyzed, and measures to prevent stress corrosion cracking were put forward to ensure long-term operation of the device.