The invention provides an OLED backboard and manufacturing method thereof, and a display device. The OLED backboard includes a substrate and a plurality of organic light-emitting diodes formed on the substrate, each organic light-emitting diode includes a bottom electrode, a top electrode, and organic luminescent materials between the bottom electrode and the top electrode, the thickness of the bottom electrode at the first edge area of the corresponding organic light-emitting diode is greater than that of the central area of the organic light-emitting diode, so that the conductive capability of the first edge area of the bottom electrode is enhanced, and the brightness of the organic luminescent materials at the first edge area is improved, the brightness of the organic light-emitting diodes at the first edge area and the central area is uniform, the OLED color mixing can be prevented, and the display quality of the OLED display device at a large visual angle can be effectively improved.