Abstract: The molecular dynamics simulation of Mg-Al alloy was carried out by using EAM potential in LAMMPS software. Mg-Al alloy models with different atomic number were set up, the effects of Al content on the thermal properties and atomic structure of the alloys were studied. Based on energy-temperature curve and specific heat capacity-temperature curve, the melting point and enthalpy of Mg-Al alloy during the heating process were studied. The results show that the melting point of the alloy decreases first and then increases with the increase of Al content. When the Al content is 50at%, the melting point is lowest. The density and specific heat capacity of the alloy decrease with the increase of Al content, and the thermal conductivity increases first and then decreases with the increase of Al content. The simulation results show that α-Mg₃Al₂ eutectic impurities may be generated in Mg-Al during the heating process, which affects the specific heat capacity and melting enthalpy of the whole alloy system.