The invention provides a subsynchronous oscillation suppressing method and device for a wind generation set. The subsynchronous oscillation suppressing method includes: acquiring a stator current signal of a wind generation set in a synchronous rotation coordinate system, and calculating the subsynchronous oscillation frequency according to the stator current signal; querying and acquiring a phaseangle deviation ratio, a phase deviation time constant, and a proportionality coefficient which are corresponding to the subsynchronous oscillation frequency according to a phase angle deviation table, a proportionality coefficient table, and the subsynchronous oscillation frequency; generating a subsynchronous oscillation control signal according to the phase angle deviation ratio, the phase deviation time constant, the proportionality coefficient, and the stator current signal; and inputting the subsynchronous oscillation control signal to a basic network side control inner loop of the windgeneration set. In a special implementation aspect, an original detection and computing performance of a network side converter in a dual-fed set is utilized, subsynchronous oscillation is suppressedthrough a software control strategy upgrading, the cost of hardware loop reconstruction can be avoided, and engineering reconstruction is facilitated.