This study evaluates the fatigue properties of corroded weathering steels to assess their long-term structural safety, durability, and economic feasibility. The fatigue life of two groups of weathering steel is measured by experiment. The first group consists of non-corroded specimens, while the second group is subjected to atmospheric corrosion for a duration of one year. The fatigue life of weathering steel is predicted by numerical calculation. It is found that the fatigue life of numerical simulation can accurately predict the fatigue life of butt weld specimens and provide a certain safety margin. The difference between the two is 2.5 %, which is a strong validation of the method. Then, Utilizing the ABAQUS and FRANC3D interactive platforms, the study achieves numerical computations for initial crack insertion and crack propagation under fatigue loading, and the influence of stress amplitude, initial crack size, initial crack shape, initial crack position, and welding dislocation on fatigue life is analyzed. Nine different stress amplitudes are simulated, and the fatigue life difference between the stress amplitudes of 117 MPa and 189 MPa being 31.72 %. Six different initial crack sizes are simulated. The initial crack sizes are 0.075 and 0.5 mm, and the difference in fatigue life between the two is 48.58 %. Four different initial crack shapes are simulated, and the fatigue life difference between the short axis and the long axis ratio of 1/4 and 1/1 of the initial crack is 30.70 %. Three initial crack positions are simulated, and the difference in fatigue life at different positions is less than 10 %. The effects of four different sets of angular dislocations on fatigue life are simulated. Angular misalignment in butt weld specimens has a minimal effect on fatigue performance, approximately 1 %, provided that the flatness requirements of the specifications are met. However, when the flatness requirements exceeded the specification, the effect on the specimen was greater than 30 %, and its effect cannot be ignored. Based on fatigue detail tests of corroded weathering steel, this paper proposes and validates a method for evaluating the fatigue life of weathering steel after corrosion, and clarifies the factors influencing the fatigue life of weathering steel structures, the proposed method can provide support for the design of fatigue details of weathering steel bridges
