The goal of this research is to know the mechanical properties of Zn-xMg alloy through the molecular dynamics method with LAMMPS software. The potential used in this computational calculation are Lennard-Jones, Morse hybrid LJ, and Stillinger-Weber hybrid LJ. Structure properties of Zn-xMg before temperature treatment is HCP with space group P63/mmc. Mechanical properties are explained by bulk modulus and elastic constant. Temperature treatment will be done before mechanical properties simulation by doing heating-cooling on the material structure that has been made before. The study of bulk modulus with a value of that appropriate to experiment is 67,492 GPa with error percentage 5,17349% that simulated by Lennard-Jones potential. Elastic constants with a value of that appropriate for C11 dan C12 is 26,198 GPa and 23,503 GPa with error percentage 14,49729% (Zn-1%Mg) and 37,02932% (Zn-5%Mg) which simulated by Morse potential, for C44 is 8,2219 GPa with error percentage 0,266362% (Zn-3%Mg) which simulated by Stillinger-Weber potential.