A lighting device for an MRI system aperture has at least one LED lamp and a light guide plate, the light guide plate having an interior surface, an exterior surface and multiple end faces. The end faces include a first end face, a second end face and one or more other end faces. Light rays from the LED lamp enter the light guide plate through the first end face, and exit the light guide plate through the exterior surface. The inner surface is opposite the outer surface, and the second end face is opposite the first end face. This lighting device for an MRI system aperture reduces the volume occupied in the MRI system aperture and at the same time the light rays are gentle and produce an effect of gradual change, protecting the examination subjects eyes and dispelling nervous feelings and claustrophobia in the examination subject.