An OLED array substrate, a manufacturing method thereof and a touch display device. The OLED array substrate includes a base substrate, a transistor on the base substrate, and a planarization layer covering the transistor. The OLED array substrate further includes a touch sensor integrated in the OLED array substrate, wherein the touch sensor is located on a side of the planarization layer facing away from the transistor, and the touch sensor includes first touch electrodes and second touch electrodes insulated from each other.