In this paper electro-optic characteristics of ZnSe have been investigated using density functional theory. The Kohn-Sham equations were solved using the full potential linear augmented plane wave approach (FP-LAPW). We used GGA, LDA+U and GGA+U approximations for the exchange correlation potential. The computations were done for energy levels from 0 to 14 eV considering the effect of d-orbital and proper choice of Ueff =U-J. The width of band gap has been corrected so that it is much closer to experimental result. The theoretical values of band gap and the refractive index have been improved comparing to their experimented values.
