Abstract: HEMP coupling tests of the cable near ground were conducted. The relations of inducing skin current of shielding layer, core voltage and core current with the environment field were obtained. The change of shield layer current wave with grounding state of external shield and core voltage with loading resistance was analyzed. According to the dependence of shield layer current oscillating frequency on electromagnetic wave propagation velocity, conception of transporting line of shield layer-ground with equivalent relative dielectric constant was presented. fited equation of equivalent relative dielectric constant with change of cable height was given. There a good coincidence in the calculation of shield layer current and measuring results in the aspect of waveform, oscillating circle and a