In order to suppress the influence of link voltage fluctuations and load changes on subway auxiliary inverter output voltage, a multi feedforward PID compound control strategy was proposed based on output voltage instantaneous value feedback, link voltage and output current feedforward. The design methods of the feedback controller and the multi feedforward controller were described. The simulation verification of the proposed control strategy was performed by using Matlab/Simulink simulation software. At the meantime, the experiment was carried out in a 200 kVA subway auxiliary inverter prototype which had a DSP+FPGA control system.The simulation and experiment results demonstrate the proposed control strategy makes the auxiliary inverter meet the industry standards well with the advantages of stable output voltage wave, low THD, better anti-disturbance ability and fast dynamic response.