The invention discloses a method for suppressing sub-synchronous oscillation based on near-end phase locking of a power network. In the original grid-connected vector control, the control structure ofthe phase-locked loop is changed, and the calculated near-end phase angle of the power network is taken as a reference phase angle of grid-connected vector control coordinate transformation. The invention also discloses a subsynchronous oscillation suppression system based on the proximal phase lock of a power network. The invention can weaken the sub-synchronous component in the output phase angle of the phase-locked loop, weaken the sub-synchronous oscillation generated by the coupling of the phase-locked loop and each link of the vector control, and at the same time does not need to increase the extra cost.