Abstract: With gas-kinetic unified algorithm (GKUA) based on Boltzmann equation for various flows regimes, rotational non-equilibrium effect is investigated in Rykov model, in which spin movement of gas molecules is described with moment of inertia. Numerical method of Boltzmann model equation involving rotational non-equilibrium effect is developed. Nitrogen shock wave structure, flows around a 2D blunt-head body and flows around a 3D tine bicone are simulated to validate the method in various flows regimes.