Abstract: As the high-power IF furnace contains frequency conversion device, the effects of harmonics injected into the power grid cannot be ignored. In this paper, the working principle and power supply structure of IF furnace are introduced in detail. Based on the Advanced Digital Power System Simulator(ADPSS) ,and taking a steel plant project accessed to East Inner Mongolia power grid for an example, the electromagnetic transient model of IF furnace is established and simulated. The harmonic analysis method combined the time domain simulation with the recursive discrete Fourier algorithm (DFT) is used to obtain the harmonic characteristics of the IF furnace. An electromagnetic transient harmonic control model based on active power filter is established, and the validity and correctness of the proposed model and harmonic analysis method are verified by simulation. The harmonic pollution of IF furnace access to power grid is reduced, and the power quality of the grid is improved.