Abstract: Aiming at the problem of signal distortion and interwire coupling, the finitedifference timedomain（FDTD)method for nonuniform multiconductor transmission lines（MTL)is presented.Firstly，the simulation model for nonuniform MTL is discussed.Then，the voltage response of transmission line is analyzed using MATLAB programming.The results show that the FDTD method is correct and efficient for the electromagnetic compatibility（EMC)， providing valuable reference for prediction of electromagnetic interference（EMI).