The electronic structure and spectrum of laser crystal MgO:Ni

2+

are investigated. The theoretical method used includes a DV-X

α

method of calculating electronic structures and spectra of transition-metal com-plexs supposed

[1]

. It has taken account of the multiplet effects arising from the metal-ion 3d electrons by extending the one-electron DV-Xa calculation and incorporating with Bird's molecular orbital description of Ligand-field spectra.The one-electron energy levels

total density of states

spin polarization splitting and spin-orbital coupling constant are given. The charge transfer transition energy is calculated with the transition state theory. All the crystal-field transition energies are obtained by calculating the two-electron integrals based on results of the spin-restricted one-electron DV-X

α

calculation. Results obtained are in good agreement with the experimental ones.