The Cu-Al2O3-MgF2-Au double-barrier tunnel junction has been fabricated. In this structure the electron resonant tunneling occur when a bias voltage is applied because of the existence of a series of separated energy levels in the barrier.Together with the analysis of I-V characteristics of the junction, the light emission properties have been discussed in detail.It shows that the light emission efficency,light emission stability etc,have been improved greatly.The light emission spectrum shifts towards short wavelength region as compared with that of the single-barrier metal/insulator/metal junction.