© 2015, Gazi University Eti Mahallesi. All rights reserved.The structural, electronic, optical properties and elastic constants of Be1-xZnxSe alloys were studied thoroughly using a program called CASTEP that grounds on the density function theory (DFT). The exchange correlation, GGA (Generalized Gradients Approximation) was also used. The elastic constants, mechanical properties, forbidden band gap, Kleinman parameter, dielectric constants, refractive index, absorption coefficient, and loss coefficient calculations have been calculated for these compounds. In addition to this, elastic constants, and bulk modulus were obtained via an X-Ray values depending on Vegard’s law. As an important result, the bulk module and forbidden band gap decreases with Zn doping to the structure. The obtained results are consistent with the available experimental and theoretical values.