An OLED array substrate and a method for manufacturing the same, an OLED packaging structure and a display device are provided by the present disclosure. The OLED array substrate includes thin film transistors, anodes, cathodes and organic light-emitting layers arranged between the anodes and the cathodes. The OLED array substrate further includes spacers configured to support the OLED array substrate and a packaging substrate so as to form a cell gap therebetween. Each cathode includes a first region which covers the corresponding first spacer and a second region beyond the first regions, and a thickness of the cathode at the first region is larger than a thickness of the cathode at the second region.