Abstract: The equipment circuit method is introduced to obtain the transient response of the lossy non-uniform transmission line network with nonlinear terminations. After modifying the equipment circuit model of the lossy transmission line, a lossy non-uniform transmission line equivalent circuit model is introduced in this paper. Meanwhile, the transient responses for a lossy microstrip line with linear and nonlinear terminations excited by the designed electromagnetic pulse source are simulated. The results of the simulations and the experiments are consistent with each other, which verifies that the models are correct. A typical lossy non-uniform transmission line, a typical unequal length lossy non-uniform transmission line, and a typical lossy non-uniform transmission line network are simulated. The simulation results are in good agreement with those of the finite difference time domain(FDTD) method and the conventional lumped method.