The invention discloses a display panel and a manufacturing method thereof and a display device, and belongs to the technical field of displaying. The displaying panel comprises a color film substrate and an array substrate which are closed to form a cell, and the color film substrate comprises a lining substrate and multiple color resistance units which are formed on the lining substrate and arranged in an array mode; each color resistance unit comprises at least two kinds of color resistance blocks, and the color resistance units comprise at least one color resistance adjusting unit, wherein in each color resistance adjusting unit, the thickness of the first color resistance block is larger than that of the second color resistance block; a hierarchical structure is formed by overlapping all prearranged film layers on the display panel, the absorption rate of the hierarchical structure to light with the wavelength corresponding to the first color resistance blocks is lower than that of the hierarchical structure to light with the wavelength corresponding to the second color resistance blocks, and the prearranged film layers are different from film layers where the color resistance units are located. Accordingly, the problem that the display effect of a display panel is poor is solved, the display effect of the display panel is improved, and the display device is applied to the display panel.