A pixel array, a method for fabricating the same, and an OLED array substrate are disclosed. The pixel array includes a plurality of pixels, wherein each pixel includes four sub-pixels, the four sub-pixels are of the same size and all in a shape of isosceles trapezoid, and the four sub-pixels are arranged into a form of half of a regular hexagon. A display panel having the above structure has a better rotational symmetry, as a result, a high resolution and homogeneity can be achieved for each direction of the display panel.