This work is assigned to study the influence of different interaction potential forms on the pressure and internal energy of crystalline argon along its isothermal curves at high temperatures, expanded from melting point temperature up to room temperature at different molar volume values expanded up to its value, corresponded experimental equilibrium curves with gaseous and liquid phases within the framework of quasi-classical approximation. The pair-wise inter-atomic forces in conjunction with three-body forces were taken into consideration. The results of this study regarding the pressure and internal energy of crystalline Argon were compared with available experimental data. The comparison clearly indicates that the calculated results coincide well with the experimental results.