Fatigue tests were conducted on centrally notched aluminum alloys 2524-T3 and 7050-T7451 under constant-amplitude and actual random spectrum loading in dry air and in 3.5% NaCl sodium chloride solution, and fatigue damage mechanisms under the load interaction and the corrosion effect on fatigue crack initiation and propagation were deduced from fractographic analysis. Pure and corrosion fatigue lives under actual random spectrum load history were modelled based on a modified accumulation damage algorithm accounting for the load interaction. More reasonable predictions were achieved from the modified algorithm proposed in the paper than from the Palmgren–Miner rule.