Abstract: When flying at extremely high Mach numbers at low and medium altitudes, the new hypersonic vehicles will encounter a complicated flow environment, i.e. the coupling between turbulence and chemical non-equilibrium. However, there are only very few related studies so far. In this work, direct numerical simulations (DNS) were performed for the high-temperature and non-equilibrium turbulent boundary layer after the leading shock of a cone using two different gas models, i.e. the calorically perfect gas model and the chemical non-equilibrium gas model. The Walz equation, the strong Reynolds analogy (SRA) relation, the turbulent kinetic energy production-dissipation mechanism and the compressibility effects were compared and analyzed. The results show that the weak compressibility hypothesis still holds in the chemical non-equilibrium turbulent boundary layer. When using the relation between the non-dimensional recovery enthalpy and the velocity, effects of the Mach number, the chemical reaction, etc. can be eliminated, and the prediction agrees well with the DNS result. GHSRA (Generalized Huang’s SRA) is appropriate to describe the relation between the temperature fluctuation and the velocity fluctuation. The ‘semi-local’ scaling can collapse the distribution profiles of the turbulent kinetic energy budgets under different flow conditions. The compressibility effect caused by the chemical non-equilibrium and the high Mach number is limited.