Abstract: Abstract After the construction of a certain aluminum alloy window frame, white crystalline corrosion products appeared on its surface. The cause of window frame corrosion was analyzed using macroscopic observation, chemical composition analysis, coating thickness measurement, infrared spectroscopy analysis, scanning electron microscopy and energy spectrum analysis, X-ray diffraction analysis, metallographic examination. The results show that due to improper construction, the surface coating of the aluminum alloy window frame was damaged, and corrosive ions such as (SO₄)²⁻, Cl⁻, (OH)⁻ were present in acid rain and humid environments, ultimately led to corrosion of the aluminum alloy window frame.