Abstract: Corrosion tests on copper under static NaCl electrolyte layer were carried out in applied magnetic field. The effect of horizontal magnetic field on corrosion product evolution of copper under electrolyte layer was investigated through scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the corrosion products of copper consisted of loose outer layer with Cu₂(OH)₃Cl and dense inner layer with Cu₂O in the environment of NaCl electrolyte layer coupling with magnetic field. The magnetic field did not change the corrosion mechanism of copper under electrolyte layer, but accelerated the corrosion process and changed the morphology of corrosion products. After 30 days of corrosion, spherical Cu₂(OH)₃Cl grains formed on the surface of the corrosion product layer.