Abstract: In this paper, a hybrid BLT-FDTD approach has been used in analyzing the time-domain response of coupledtransmission lines contains the non-uniform lines. An FDTD code is used to compute the non-uniform lines which is drawingout of the whole transmission network, then transformed to the frequency domain and incorporated into a BLT equation to solvethe response of electrical voltage and current. The advantage of this approach is that, on one hand, avoiding the more calculationand more impropriation of CPU which brought by the discrete space to the whole transmission lines using FDTD. On the other hand, taking the non-uniform lines as a node provides a new idea for the solution of complicated transmission network onfrequency-domain. The simulation results present the efficiency of this method