The aim is to resolve the difficulties of measurement of temperature at several thousands of Celsius degrees for some unstable non-equilibrium gas flows. Based on the molecular spectroscopy theory and inherent molecular structure characteristics of the CN radical, the dependence of the spectral profile on the rotational temperature (RT), vibrational temperature (VT) and optical apparatus function are numerically explored within some certain ranges. Meanwhile, by comparing the numerically calculated spectra with the experimental spectra of the CN radical, the corresponding RT and VT of the plasma induced by the interaction of the laser pulse from an oscillated Nd:YAG laser with the coal target are determined, respectively. In addition, a short discussion on the thermodynamic state and the energy transfer process of the CN radical is also given
