Abstract: The pulse steepening technology of ferrite transmission lines can realize high-frequency and high-power fast front pulse output and has the advantages of solid-state and compactness. It has been widely used in high-power microwave sources. The simulation calculation of pulse steepening characteristics of ferrite transmission lines lacks a more accurate model. Therefore, this paper establishes the simulation model of the ferrite transmission line by using COMSOL simulation software, considering the interaction between electromagnetic wave propagation and magnetic core magnetization precession. The Maxwell equation and Landau-Lifshitz-Gilbert (LLG) equation are combined for simulative calculation. Compared with the experimental results, the accuracy of the simulation model is verified. Based on this model, simultaneous interpreting of the effect of different transmission line lengths, voltage amplitude, and external bias magnetic field on pulse waveform is studied. The results show that the pulse front decreases with the increase of transmission line length and the increase of voltage amplitude; The output of the minimum pulse front can be realized by selecting an appropriate external bias magnetic field.