Abstract: Failure of heat exchanger at the top of atmospheric column was analyzed by chemical composition analysis,macro examination and micro-analysis,and the corresponding countermeasure was pointed. Results showed that chemical composition of heat exchanger met the design requirement,and the main failure reasons was the encrustment in the system,which led to the corrosion under the deposition. Therefore,replacement management of inhibitor used in atmospheric column system should be strengthen and quality of water added in the system should be improved to control and decrease the corrosion in the system.