Abstract: Cyclic accelerated corrosion tests were conducted on weathering steel in two simulated marine atmospheric environments: dark conditions and ultraviolet (UV) radiation. The corrosion behavior of the weathering steel in these two environments was evaluated through electrochemical tests, morphological observations, and phase composition analysis. The results indicate that the UV-irradiated marine atmospheric environment influenced the corrosion process through the photoelectric effect of the corrosion products. The introduction of photoelectrons altered the redox reaction process between the test steel and the atmospheric environment, enhancing the electrical conductivity of the corrosion products, promoting the densification of the rust layer, changing the phase composition of the corrosion products, and improving the atmospheric corrosion resistance of the weathering steel.