The invention provides a display panel and a preparation method thereof and a
display device, the display panel comprises a bearing substrate, a pixel defining layer and a color conversion layer, scattering particles are arranged in the pixel defining layer, the pixel defining layer is arranged on one side of the bearing substrate, the pixel defining layer is arranged in an array and forms a plurality of opening areas, and the color conversion layer is arranged on the bearing substrate. The color conversion layer comprises a plurality of color conversion parts, the color conversion parts are arranged on one side of the bearing substrate, the color conversion layer is arranged in the opening area, the size of the end, away from the bearing substrate, of the pixel defining layer is larger than that of the end, close to the bearing substrate, of the pixel defining layer, and the pixel defining layer forms an inverted trapezoidal structure with the wide upper portion and the narrow lower portion; the inclined side wall of the inverted trapezoid is equivalent to a light blocking screen, large-angle light rays can be blocked by the inclined side wall, the light rays are prevented from entering adjacent pixels, the phenomena of light
ray crosstalk, light mixing, large-viewing-angle color cast and the like of the display panel can be greatly reduced, and the display effect of the display panel is further improved.