The present invention provides a transparent window display apparatus, which includes a diffuser plate, in addition to a transparent display screen, a top plate, a back plate, a base and two side walls, the diffuser plate and the back plate form an angle and at least one light source is provided between the top plate and the diffuser plate. By adjusting the light source between the top plate and the diffuser plate, planar light is provided for both show of an exhibit and display of the transparent display screen simultaneously, dual purposes of window display and advertisement display can be achieved, and meanwhile, costs are saved and efficiency is improved.