The role of electronically excited states (EES) in the thermophysical properties of a ternary Ar-He-H-2 mixture has been examined in the temperature range from 6000 to 40000 K at pressures of p = 0.1, 1.0, and 5.0 atm in local thermodynamic equilibrium (LTE). The influence of electronic excitation was observed to be enhanced with increasing pressure, and for pressures from p = 0.1 to 1.0 atm, the enthalpy, frozen specific heat, total specific heat, electrical conductivity and electron thermal conductivity were enhanced by 1.22%, 30%, 5%, 11..5%, and 2%, respectively, whereas for pressures p = 1.0 to 5.0 atm, the enhancements in these properties were 2.8%, 20%, 6%, 4.5%, and 14.3%, respectively. At; higher pressures (p = 5 atm), pronounced contributions to these properties of 11%, 62%, 26%, 18%, and 28%, respectively were noted. Due to the significant contribution of electronic excitation to these properties, considering its influence in modelling plasma processes is important.