Abstract: The relationship between the metal material density and temperature was deduced from thermal expansion analysis based on solid physics microscopic theory. The material densities at different temperatures calculated by applying the relationship agreed well with the experimental data. On the basis of the discussion about the relationship between the elastic constants and interatomic potentials of metals, some advices on energy potentials configuration choice were provided. A new approach of molecular dynamics simulation was developed to calculate the elastic constants of metals based on the influence of temperature change by adjusting crystal parameters including structure and density. The corresponding computation procedure is described and it can provide a new method to analyze the material properties at high temperatures. Examples of computing elastic modulus and poisson ratio at room-temperature and 912 ℃ were given by applying the proposed method. The results were in a good accord with known test data.