Given that the ability of doubly-fed induction generator（DFIG） to sustain power grid low voltage is mostly restricted by the overcurrent capacity of the converter at rotor side， appropriate control rules to avoid serious rotor overcurrent is key to keep DFIG connected with grid safely during voltage dip and voltage recovery. In order to improve the dynamic characteristics of rotor current， decoupling control strategy based on the 5th order model is proposed. It eliminates the adverse effects for rotor current dynamics by feedforward compensation considering transient stator flux. The corresponding control parameter design method is proposed as well. Simulation results show that the proposed strategy can quickly track the rotor current reference and restrain overcurrent so as to enhance DFIG's low voltage ride-through capability. The results also verify the validity and availability of decoupling control strategy. The proposed method can be used in the parametrical designing method of DFIG considering its dynamic characteristics.