A manufacturing method of an array substrate, an array substrate and a display device are provided. The method includes the following operations: forming a light shielding layer formed of a metal blacken production on a base substrate, wherein the metal blacken production is a product by blackening a metal; forming a preset film layer on the base substrate which is provided with the light shielding layer; forming both a pattern of the light shielding layer and a pattern of the preset film layer through one patterning process. The method of forming a pattern of the light shielding layer and a pattern of the preset film layer through one patterning process saves one patterning process.