The present disclosure provides an organic light emitting diode array substrate and its manufacturing method, as well as a display device. The organic light emitting diode array substrate includes: gate lines, data lines, and a plurality of pixel units defined by the gate lines and the data lines. Each pixel unit comprises a first region which emits light and a second region which does not emit light. The first region is provided with an organic light emitting diode, and the second region is provided with a conductive unit which is electrically connected in parallel with the data line and created from the same layer from which a cathode of the organic light emitting diode is created.