Thermophysical properties of the complex metal hydride system such as zirconium cobalt hydride, an intermetallic hydride compound, in a massive state were estimated by introducing a crystal lattice structure in a stepwise formation and applying a mixing rule for each property. Experimental data in rarity in metal hydride system was used to calculate and to correlate the consistency of the mixed thermal and physical properties of the complex atomic structure in a unit cell. As a result, the volume expansion of the ZrCoHx was greatly influenced by the hydrogen content and increased to a maximum range of 36% at ZrCoH3 system, but no meaning in the thermal expansion in engineering concept. In consideration of the heat capacity the temperature effect due to the hydrogen an interstitial heat quantity in the metal complex formation was mainly attributed, but not much for the hydrogen content (H/ZrCo ratio). In the temperature range between 200K and 600K the heat capacity of hydrogen atom was taken into account to reveal a sharp discrepancy in its non-hydriding property, especially in the lower temperature range. Atomic hydrogen was expected to behave from a gas to a solid property in heat capacity in the temperature ranges from 600K to 200K.