The present disclosure discloses a manufacturing method of an array substrate, an array substrate, a display panel and a display device. The manufacturing method comprises: forming a shielding layer on a base substrate, wherein the shielding layer absorbs light and is made of photoresist; and forming a transistor device layer on the base substrate on which the shielding layer is formed, wherein an orthographic projection of a conductor in the transistor device layer on the base substrate is within an orthographic projection of the shielding layer on the base substrate. The shielding layer can prevent external light from irradiating the conductor in the transistor device layer, and can absorb external light. In addition, the manufacturing process is simple.