Abstract: Nonlinear response of cable irradiated by X-ray is simulated using numerical method. The physical processes of the X-ray irradiating to cable are analyzed. Norton-equivalent driver model is built up for coaxial cable or shielded multi-cable based on 2-dimension finite-element method, focusing on dielectrics radiation-induced conductivity effect. The nonlinear responses of Norton-equivalent driver are calculated and their regularities are concluded in detail. The simulation result showed that the current amplitude would reach a saturation value as the X-ray fluence increased when induced conductivity existed. For some types of cable, there would be 3 different current peaks appearing successively at different point on the waveform while the X-ray fluence increased.