An array substrate, a method of preparing the array substrate, and a display panel are provided, the method of preparing the array substrate includes: providing a base substrate; forming a plurality of light emitting devices arranged in an array on the base substrate; covering the base substrate, on which the plurality of light emitting devices are formed, with a black matrix material; activating the plurality of light emitting devices to expose the black matrix material; and developing the exposed black matrix material to form a black matrix.