A novel method in time domain for the response of high power EMP with braided-shield multiconductor cable is proposed. The current on the shield can be used as the stimulus of the MTL equations based on the definition of the transfer impedance. The current on the shield, the core current and the core to shield voltage are obtained by the FDTD method combining the MTL equations with the field equations. A comparative study is carried out against the transfer impedance models proposed by Vance and Tyni. As an example of the application of the FDTD-MTL method, the response of high power EMP with three-conductor braided-shield cable is obtained.