Abstract: The influence of the chemical kinetic model selection on the computation of the hypersonic flow in the thermochemical nonequilibrium state is examined, with consideration of several different chemical reaction models (the Dunn-Kang model, the Park85 model, the Park93 model, the Park2001 model, and the Gupta model). Typical experimental results at home and aboard are used to identify the reliable model. The thermal nonequilibrium processes in the gas are accounted in the Park's two temperature model. Cases are computed using five species, and one temperature model is used for comparison. It is shown that the Park85-7 species-two temperature model gives the best results, as compared to experiment data. On the other hand, the Park85-5 species-one temperature model is more suitable for engineering applications.