The invention relates to the technical field of a power network, and discloses a subsynchronous oscillation inhibition apparatus and method for inhibiting flickering of a power network. The apparatus comprises a velometer connected with a generator set for detecting rotating speed signals of the generator set; a controller connected with the velometer for comparing the rotating speed signals detected by the velometer with standard rotating speed signals to obtain rotating speed deviation signals of the generator set and successively performing modal filtering and proportional phase shift on the rotating speed deviation signals so as to generate active current instructions and reactive current instructions; and a subsynchronous oscillation inhibiter connected with the controller for generating active currents and reactive currents which are corresponding to the active current instructions and the reactive current instructions under the driving effect of the controller and injecting the active currents and the reactive currents into the generator set and the power network so as to inhibit subsynchronous oscillation through the reactive currents and inhibit flickering of the power network through the active currents. The apparatus and method provided by the invention solve the problem of proneness to power network flickering in inhibition of the subsynchronous oscillation.