Abstract: SIn response to the abnormal higher-order harmonic voltage issues in the power supply and distribution system of a port, on-site harmonic testing and customized data analysis were conducted. It was identified that the higher-order harmonic currents generated by the operation of port handling equipment (quay cranes) underwent resonant amplification. The mechanism and influencing factors of this higher-order harmonic resonant amplification were theoretically analyzed. Modeling and simulation based on actual distribution system parameters were performed for validation, confirming the existence of a parallel resonance problem with harmonic currents under current conditions. Finally, a mitigation measure based on distribution network impedance reconstruction technology was proposed, which can effectively address the resonant amplification of higher-order harmonics in the port"s power supply and distribution system.