A composite film layer, a method for manufacturing the same, and a method for manufacturing an organic light emitting diode (OLED) display panel are provided. The composite film layer includes first sub-film layers and second sub-film layers having different refractive indices, wherein the first sub-film layers and the second sub-film layers are alternately stacked, and thicknesses of the first sub-film layer and thicknesses of the second sub-film layer gradually increase or decrease in a direction perpendicular to the composite film layer.