Abstract: The bending pipe of the water-cooled wall of a furnace in a thermal power plant exploded during service, leading to the shutdown of the whole unit. Chemical composition analysis, macroscopic inspection, microstructure examination and inner oxidation skin analysis were carried out to analyze the explosion cause. Scale corrosion and acid corrosion occurred at the welding pores. After a long time of scale corrosion and acid corrosion, welding pores gradually extended outwards until the wall was penetrated and leakage occurred, resulting in reduced media flow and a short period of overheating at the upper part. Finally, the pipe exploded. For this accident, it is recommended that the power plant conduct relevant inspections on the pipe systems in the vicinity of the two explosion positions, determine the pipe replacement area based on the inspection results, increase the temperature measurement points at the regions with similar structure and higher temperature, and strengthen monitoring during operation.