The present disclosure provides a transparent OLED substrate, a display panel, and an OLED substrate. The transparent OLED substrate includes: a base substrate; a first electrode layer formed over the base substrate; a pixel defining layer formed over the first electrode layer, the pixel defining layer including a plurality of pixel defining holes penetrating the pixel defining layer to the first electrode layer, and an exposed area of the first electrode layer is equal to an area of the pixel defining hole; a light emitting layer formed over the pixel defining layer and including organic light emitting blocks; a second electrode layer formed over the light emitting layer; wherein each of the pixel defining holes corresponds to a plurality of the organic light emitting blocks.