Abstract: To achieve exact analysis of non-equilibrium flow within arcjet, numerical calculations of chemical kinetics, thermodynamic properties, transport properties, and electromagnetic characteristics of high energy flow with dissociation and ionization were carried out. A finite rate chemical kinetic model was adopted to compute the components under dissociation and ionization. The curve fits based on partition function approach and virial coefficient method were used to calculate the thermodynamic properties, and the mixing laws from the classical Chapman-Enskog procedure were introduced to obtain the transport properties of multicomponent gas mixtures. The electrical conductivity and electronic mobility were estimated by formulas derived from the motion equation of electrons and the statistical mechanics. The thermophysical properties of nitrogen under dissociation and ionization are presented by the calculations in the range of 3.0×10³ to 2.0×10⁴ K and 0.1 Pa to 1 MPa.