Abstract: In order to investigate the voltage of the load terminated between unshielded twisted pair（UTP）coupled with lightning electromagnetic pulse（LEMP），we simulated LEMP within the bounded-wave transmission line which was input with a lightning surge signal produced by WU- 800- type MARX generator and conducted the relevant experiments towards twisted- pair lines radiated by LEMP. We change the length of UTP，angles between LEMP and UTP，waveforms of LEMP as well as UTP terminal loads including linear and nonlinear loads. Results show that the amplitude of induced voltage is mainly determined by rising part of electromagnetic field waveforms and the pulse width has little effect on induced voltage. The length of the UTP under test obviously affects the response of UTP different frequency. With increasing the length of UTP，the frequency of the coupled voltage decreases and the voltage increases. The polarization direction of the electric field has a great impact on the amplitude of terminal response，but it does not change the wave?forms of induced voltage. The UTP radiated by LEMP can be taken as a voltage source for terminal load of UTP，the load voltage of test side satisfies the partial pressure principle and the load in other side of UTP changes the inner parameters of equivalent voltage source，but the effect is very small. If a diode is connected to the UTP，it will significant affect the spectral distribution of induced voltage and the amplitude will be changed at the same time.