An OLED display panel, a preparation method therefor, and a display apparatus. The display panel includes a display area including a first sub-pixel, a second sub-pixel and a third sub-pixel displaying different colors; the display area includes a first electrode layer, a pixel defining layer, an organic functional layer and a second electrode layer sequentially arranged on a substrate; the organic functional layer includes a first light-emitting layer in the first sub-pixel, a second light-emitting layer in the second sub-pixel, and a third light-emitting layer covering the display area and having an integrated structure; the orthographic projection, on the substrate, of each of the first light-emitting layer and the second light-emitting layer includes the orthographic projection of an opening on the substrate, which defines a corresponding sub-pixel, of the pixel defining layer and does not overlap with orthographic projections of remaining openings of the pixel defining layer on the substrate.