Abstarct: The Zinc Selenid (ZnSe) is one of the proto type of II–VI semi conductors materials. This compound, has a high chemical stability and direct energy gap of about 2/67eV at room temperature. In this work electronic structure and optical properties of pure ZnSe, B and Mg -doped ZnSe were investigated. Density Functional Theory (DFT) and structural and optical characteristics of ZnSe have been introduced in chapter one. Wien2k software has been presented in chapter 2. The results of optical characteristics and electronic structures of pure and doped – ZnSe,which were investigated by using DFT, have been reported in chapter three and four, respectively. Full-potential linearized augmented plane wave method were used for all calculations. Band structures, density of states, dielectric functiones, absorbtion, optical conductivity, refractive index, extinction coefficient, energy lost and reflectivity were calculated for all samples . Density of state of pure samples were showed that the upper part of the valence band, (near the Fermi level), has been composed of p-Se and s-Zn states. p-Zn states have the great part in the minimum of the conduction band that causes the formation of gap between the p states of the Se and Zn. Our Results were showed that Boron doping and its increasing are causes the reduction of gap and enhancement of the mextallic characteristics of the samples.Moreover, the number of the levels related to 2s-B states near the Fermi level and also doping of the Mg increased the band gap of the samples. Enhancement of the B and Mg concentration also increased the width of the absorbtion region.