Abstract: Based on the finite difference time domain (FDTD), the analyzes the equal length uniform and lossless multiconductor transmission lines (MTLs), and presents the unequal length nonuniform multiconductor transmission lines with considering the lossy of transmission line. Firstly, considering the lossy transmission line, iteration formulas are given about the voltage and current on the conductors. Secondly, the formulas are used to calculate and analyze the models of unequal length nonuniform lossy multiconductor transmission line. Finally, simulation results show that the presented method is effective, which provides a theoretical support for the study of unequal length nonuniform lossy multiconductor transmission line.