Abstract: With the development of the medium frequency electromagnetic induction melting technology in the iron industry,its harmonic harm to the power system becomes more and more significant.This article first analyzes the circuit structure,working principle and harmonic characteristics of the medium-voltage medium-frequency induction heating furnace.Harmonic measurements of typical working conditions were carried out for a typical 10 kV intermediate frequency furnace in a typical mechanical roll factory.By analyzing the dominant harmonic voltage and harmonic current,the distribution characteristics of characteristic sub-harmonic currents are obtained.The investigated system and equipment parameters are used for modeling and simulation verification.The simulation results show a high degree of consistency with the field survey results,which proved the practical feasibility of evaluating the harmonic characteristics of the intermediate frequency furnace through simulation calculation.It provides a tool for power quality prediction and evaluation of old or newly constructed intermediate frequency furnace equipment.