Abstract: Anti-swirl air injection time and injection location on the anti-swirl seal has a great influence on the static and dynamic characteristics. In this paper, a numerical model of anti-swirl seal active injection control is established to study the influence of pressure ratio and pre-swirl ratio on sealing static and dynamic characteristics. The results show that increasing the rotor whirling motion angles can reduce the circumferential pressure difference of the seal downstream and improve the rotor stability; axial radial injection near rotor of the air has a great impact on the effective stiffness, and the tangential injection upstream of the rotor vortex can reduce the cross stiffness and improve the effective damping. The higher the pressure ratio, the greater the pre-swirl ratio, and the more significant the optimization effect of the air on the seal stability. But it will lead to an increase in leakage. At the highest parameter of this paper, the air near rotor axis injection is 4.61% higher than the energy dissipation of the far rotor axis injection. In the tangential injection, energy dissipation of air injection at rotor vortex upstream is 3.30% higher than that located downstream of therotor vortex. When the rotor vortex angle is the same, the reverse current tangential jet is more significant than the radial jet energy dissipation.