Abstract: A low-temperature economizer tube of a waste incineration boiler experienced a pipe explosion and leakage accident. The causes of pipeline leakage were analyzed using macroscopic observation, chemical composition analysis, mechanical property testing, metallographic examination, as well as scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction analysis. The results show that there were comb-shaped plates and pipe clamps near the leakage point of the economizer tube, which resulted in poor flow of flue gas near the tube wall. The alkali metal chlorides and sulfates carried by the tail flue gas adhered to the tube wall, and activated oxidation of chlorides and sulfate corrosion occurred in a low-temperature and oxidizing atmosphere, leading to thinning of the tube wall and ultimately causing leakage of the pipeline due to insufficient pressure bearing capacity.