Abstract: In the large current-breaking process of the DC vacuum circuit breaker, the metal vapor arc plasma generated in the vacuum interrupter is closely related to the material properties of the contact electrode. In order to study the variation of metal vapor plasma physical properties parameters in the process of breaking, the non-local thermodynamic equilibrium model of vacuum arc plasma was established to obtain the composition distribution of particles of metal vapor plasma of CuCr25~CuCr75 contact. Moreover, using the statistical thermodynamic method, the thermodynamic parameters of metal vapor plasma were calculated, and the distribution of specific enthalpy and isobaric specific heat capacity with different alloy ratios were illustrated. Furthermore, the Chapman-Enskog method was used to calculate the transport parameters to investigate the effect of alloy ratio on the conductivity.