An illumination apparatus includes a first light-guide plate, a second light-guide plate and a base. Each of the first and second light-guide plates and the second light-guide plate includes a light-emitting surface, a side surface connecting the corresponding light-emitting surface, a micro-structure pattern, a circuit layer integrated with the corresponding side surface, and a color light source disposed on the corresponding side surface and electrically connecting the corresponding circuit layer. The region where the light from the color light source of first light-guide plate orthogonally emitting from is different from the region of where the light from the color light source of second light-guide plate orthogonally emitting from. The base includes a cavity for accommodating the side surfaces of the first and second light-guide plates and electrically connecting the corresponding circuit layers.