The effect of self-generated magnetic field produced by electric current on the corrosion behavior of Cu in simulated marine atmospheric environments was studied via a novel lab-made electrochemical test set, which consists of that a current-carrying copper conductor is covered with T2 pure Cu foil, and a thin electrolyte layer (TEL) on top of the Cu foil. The surface morphology and composition of the corrosion products were characterized by using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy techniques. The results showed that with the increasing intensity of the self-generated magnetic field, both the cathodic and anodic processes of the copper were accelerated, jointly leading to an increase in the corrosion rate. During long term corrosion exposure, the composition of the corrosion products on the copper surface changes with the increasing intensity of the self-generated magnetic field, while weakening its protective ability for the subsequent corrosion of Cu substrate, thus, pitting corrosion occurs on the Cu surface. At the same time, it is found that the corrosion degree of the Cu surface is closely related to the direction of the electric current and locations of the test piece, namely where the current input the corrosion degree is higher than that the current output. Herewith, the influence mechanism of the self-generated magnetic field on the atmospheric corrosion of Cu is further discussed.