Lighting return-stroke models are needed to specify the electromagnetic radiation source in studying the production of transient optical emission in the lower ionosphere, the energetic radiation from lighting, and characterization of Earth’s electromagnetic environment, as well as studying lightning interaction with various objects and systems. Electromagnetic models of the lightning return stroke that based on Maxwell’s equations allow a self-consistent full-wave solution. In this paper, the electromagnetic lightning return stroke model with distributed series inductance is disscussed. The finite difference time domain method (FDTD) is employed to calculate the spatial distribution of current along the lightning channel. The dipole technique is used to calculate the radiated electromagnetic field when the source is known. The results show that, by choosing the parameter of distributed series inductance in 2~10 μH/m, the propagation speed of lightning current are in c/3~2c/3. With the rising of distributed series inductance, the current-wave propagation speed decreases, the electric strength in the near field area increases and the attenuation become more significant over distance. The change of distributed series inductance has little effect on the magnetic field.