An organic light-emitting diode (OLED) substrate includes: a base substrate including a display region having a plurality of luminous regions and a non-luminous region separating one or more adjacent luminous regions, the non-luminous region including a plurality of first connection regions; a first electrode layer over the base substrate including a plurality of first electrodes having their projections on the base substrate cover the plurality of luminous regions; a pixel defining layer over the first electrode layer and located at the non-luminous region and defining the plurality of luminous regions, the pixel defining layer is hollowed out at the first connection regions; an electroluminescent functional layer provided over the pixel defining layer; a second electrode layer over the electroluminescent functional layer; and a plurality of conductive structures located at the plurality of first connection regions respectively, and electrically coupled to the second electrode layer.