In this paper, the electronic structure and optical properties of BN doped with different concentrations of Zn (0. 062 5, 0. 125, 0. 25) were investigated based on the density functional theory. The results show that the defect formation energies of the three systems after doping are all greater than zero, for this reason the stresses are also calculated which verifies that all of them can exist stably. B1 - xZnxN (x = 0, 0. 062 5, 0. 125) is a direct bandgap semiconductor and B0. 75Zn0. 25N is an indirect bandgap semiconductor. The bandgap of the system gradually decreases with increasing doping concentration. The doping of Zn leads to the introduction of a receptor energy level near the Fermi level, resulting in the valence band being shifted up above the Fermi level, and the doped systems were all characterized by p-type semiconductor properties. With increasing doping concentration, the static permittivity of the systems gradually increases, the peak of the imaginary part of the doped system gradually decreases, and the value of the corresponding reflectivity at the highest peak gradually becomes smaller. In the low energy region, the doped systems all enhance the absorption of light and the absorption edge red shift. The bond strengths of B—N and N—Zn bonds in the doped systems gradually increase. To sum up, it can be concluded that doping Zn atoms can effectively improve the electronic structure as well as the optical properties of BN.