The present disclosure provides an OLED array substrate, a manufacturing method thereof, and an OLED display panel. The OLED array substrate comprises a first electrode layer, a pixel definition layer, an organic material functional layer, and a second electrode layer arranged successively in a light exit direction. The organic material functional layer comprises light-emitting regions that emit light of different colors. The pixel definition layer comprises pixel regions corresponding to the light-emitting regions, and spacing regions arranged between adjacent pixel regions. Each spacing region is configured to electrically isolate adjacent light-emitting regions.