The electroluminescence effect can be observed by the micro N-typewide-gap CBN semiconductor crystal under the condition of static eletric field.The micro N-type CBN crystal was fixed on the focus of the parabolic reflector ofgrating monochromator, and the maximum value of transmission ratio and the idealsignal-noise ratio can be obtained. Under the condition of static ectric-fieldintensity (4.7×106 V?cm-1), the blue-violet light-emitting spectrum of the CBNcrystal was measured in the range from 350 to 450 nm. The construction of the CBNenergy band, which was calculated with the First-principles method, the nonlinearrelationship between current density and the ectric-field intensity that wasmeasured and the phenomenon of electrical break-down were considered together toenable us to discuss the luminescence mechanism. Finally, the authors came upwith the luminescence mechanism concerning electron migration from Γ energyvalley to X energy valley. The large number of excited electrons we talked aboutwere generated by polarization and breakdown of defect dipole before avalanchebreakdown occurred.valey; Generalized gradient approximation(GGA)