Considering the interaction between the nitrogen molecular vibration and rotation as well as the anharmonicity of vibration, together with the precise spectral constants of nitrogen molecules, which allows us to establish the exact partition function and the thermodynamic functions of nitrogen molecules by using the vibration rotor and the non-harmonic oscillator approximation. In the range of 100 to 6000 K, the author made a groundbreaking effort to systematically probe into the contribution of the translation, vibration and rotation of nitrogen molecules to the molar internal energy, relative molar enthalpy, isobaric molar heat capacity, standard molar entropy and standard molar Gibbs free energy. The calculated results agree well with the experiment and theory. It indicates that the calculated thermodynamic parameters of the nitrogen are accurate and credible in the range of 100~6000 K, and also provides a method for calculating the thermodynamic parameters accurately.
