The invention discloses an organic light emitting display panel and a manufacturing method thereof, and a display device. Specifically, the invention provides a method for manufacturing an organic light emitting display panel, which includes the following steps: a substrate is provided, and a cathode layer is formed on the substrate; a photosensitive active layer is formed on one side of the cathode layer away from the substrate, wherein the hydrophobicity of the photosensitive active layer can be changed under illumination; hydrophilic illumination treatment is performed on the photosensitiveactive layer, and multiple openings arranged in an array are formed in the photosensitive active layer through a first composition process, wherein the orthographic projections of the openings on thesubstrate are within the area of a pixel definition layer; hydrophobic illumination treatment is performed on the photosensitive active layer except a predetermined area; and metal is deposited on one side of the photosensitive active layer away from the cathode layer, wherein the metal is formed on the photosensitive active layer and forms an auxiliary cathode through hydrophilic illumination treatment, and the auxiliary cathode and the cathode layer are connected through the openings. By using the method, an auxiliary cathode with good performance can be easily manufactured, and the use performance of the organic light emitting display panel can be improved.