[en] The energy levels of spectrum, wavefunctions and crystal-field parameters of MgAl₂O₄:Cr³⁺ at normal pressure have been calculated by the means of diagonalizing the complete d³energy matrix (DCEM). With these results, the g factor of the ground state at normal pressure and the pressure-induced shift (PS) of the spectral levels are also calculated uniformly, and the calculated results are all in good agreement with the experimental ones. And the contributions of various crystal-field parameters to the energy levels at normal pressure and the variational rates of the R₁ line shifting with the pressure are calculated, from which the physical origin of the red shift of the R₁ line shifting with increasing pressure have been clearly shown