An organic light-emitting source includes a light-guiding substrate, at least one light-source area and a reflecting layer. The light-guiding substrate has a first surface and a second surface. The first surface includes at least one light-guiding part, which is a light guiding structure disposed on the light-guiding substrate. The light-source area includes at least one organic electroluminescent device, which sequentially includes a first electrode, at least one organic functional layer and a second electrode disposed over the first surface of the light-guiding substrate. The reflecting layer is disposed over the second surface of the light-guiding substrate.