Abstract: In recent years,due to the continuous access of large-scale new energy bases to the power grid,which leads to the reduction of system rotational moment,resulting in the problem of sub-synchronous oscillations. To this end,the suppression strategy of subsynchronous oscillation of new energy base based on active damping is proposed,which attaches the active damping controller to the active power loop of the new energy grid-connected device. The suppression strategy realizes the amplitude and phase correction of output signal in oscillation frequency band by collecting the grid frequency,improves the damping characteristics of the system,so as to enhance the stability of the system. On this basis,the parameters of active damping controller are optimized and designed and it is verified by the eigenroot analysis and Prony algorithm. Finally,the regional power grid of certain city is taken as an example for simulation analysis,when the sub-synchronous oscillation occurs in this power grid,the active damping control will be attached to the new energy base,which can quickly suppress the sub-synchronous oscillation and improve the system damping,the applicability and effectiveness of active damping control are verified.