Abstract: A new electromagnetic shielding material named energy selective surface is introduced in this paper. The shielding theory and the configuration of the material were analyzed. The impedance of the material and the relationship of incident electric field strength and the transmission electric field strength were studied. The protection ability was tested on the effect of continues wave and electromagnetic pulse (EMP). The results show that the protection ability rises with higher of irradiation electric field strength, and delay time that the material has the protection ability becomes shorter with higher of irradiation electric field strength. On the effect of EMP, the material has no protection ability with narrow pulse, because the diode needs delay time to enter conducting state, and the pulse width is shorter than the delay time of the diode. In the end, some solutions are put forward for the protection of EMP.