With the increasing proportion of power electronic equipment in the microgrid of the park, the problem of harmonic pollution is becoming more and more serious, which brings challenges to the safe and stable operation of the microgrid in the park. Flexible in-terconnection device (FID) based on power electronic devices can realize power mutual aid between different distribution stations in the campus microgrid, and can provide voltage and frequency support when the distribution station area fails. Firstly, the structure, mathematical model and operation mode of FID are introduced. Then, the FID control strategy with the function of harmonic current control in the distribution station area is proposed, and the harmonic current control in the distribution station area is realized on the basis of power mutual aid, which improves the power quality and FID equipment utilization rate. Finally, the effectiveness of the proposed control strategy is verified by MATLAB/Simulink simulation and StarSim hardware-in-the-loop semi-physical experiment.