Embodiments of the present invention relate to a display substrate and fabricating method thereof and a display device. The display substrate comprises a plurality of pixel groups, wherein each of said pixel groups comprises a plurality of color sub-pixels and a plurality of white sub-pixels. A first driving transistor is provided in a light emitting layer missing region of the color sub-pixel, for driving the color sub-pixel. A second driving transistor and a white sub-pixel are provided on the first driving transistor, the second driving transistor for driving the white sub-pixel. According to the technical solution, white light OLED display may be implemented by forming the white sub-pixel and the driving transistor thereof on the driving transistor of the color sub-pixel, while making use of the space on the thickness dimension of the color sub-pixel, so that the light emitting layer missing region in the color sub-pixel is fully utilized.