As the amount of new energy injected into the power system increases, the inertia level of the power system continues to decrease. The low inertia characteristics of power system seriously deteriorates the frequency immunity of the system, and the ability of the system to maintain frequency stability be-comes weaker. For the above problems, this paper investigates the role of adding asynchronous condenser to support the frequency response of new energy power system. Firstly, analyse the operating characteristics of asynchronous condenser and study the additional power control strategy of asynchronous condenser. Secondly, establish an active frequency response model for the participation of the asynchronous condenser in the grid frequency control, and analyse the influence of the control parameters of asynchronous condenser on the frequency characteristics of power system. Finally, a simulation model of new energy power system containing asynchronous condenser is established, which verifies the ability of the asynchronous condenser to improve the frequency response characteristics and provides effective measures to improve the frequency immunity of the system.