The invention provides a display panel and a manufacturing method thereof, and a display device, belongs to the field of display device manufacturing technology, which can solve the following problem in the existing display device: when light transmits the cathode layer which is thin, has high resistance and thus poor conductivity, the display effect is nonuniform. The display panel of the invention comprises a first substrate and a second substrate which are assembled, wherein the second substrate is provided with an organic electroluminescent device thereon, an anode layer of the organic electroluminescent device is away from the first substrate and an cathode layer thereof is close to the first substrate; and the cathode layer is electrically connected to an auxiliary electrode on a light entering surface of the first substrate through a plurality of conductive spacers spaced at certain intervals, wherein the cathode layer is a transparent electrode layer.