Abstract: Stealth technology is the high technology of the national defenses focused by countries over the word. Plasma stealth is a new type of stealth technology. In this paper, the physic model of the plasma stealth is built up. Two different basic theories for plasma stealth are showed, one is refraction, and the other is the absorption attenuation. The relation between the attenuation of electromagnetic waves and the plasma collision frequencies, the electromagnetic wave frequencies, the plasma thickness is studied. And the result of calculating simulation show the plasma stealth technique is a feasible method.