The electroencephalogram generated by light stimulation in human body of dark adaption state was measured and analyzed in the cases that electromagnetic wave was put in and not put in, respectively. Shieldroom being able to interrupt the light and the electromagnetic wave of outer was constructed, and the experimental system being able to apply any light and any electromagnetic wave was designed. When the electromagnetic wave was applied to body or not, the variation characteristics of each component in the electroencephalogram were i3s follows. The 6 wave was increased and the $alpha$ wave and the $eta$ wave were decreased in the case that the electromagnetic wave was applied, and the variation range of the $Theta$ wave was small. And the influence of electromagnetic wave on human body was that the appearance time of the $eta$ wave was late, and it moaned that the time of visual recognition was delayed.