Array substrate and preparation method thereof, display panel and display device

The invention discloses an array substrate and a preparation method thereof, a display panel and a display device.The array substrate comprises a substrate, a first metal layer, a first insulating layer, a second metal layer and a liquid crystal orientation layer, and the first metal layer, the first insulating layer, the second metal layer and the liquid crystal orientation layer are located on one side of the substrate in a stacked mode; the thickness of the first insulating layer in the display area is smaller than that of the first insulating layer in the non-display area; in the non-display area, the vertical projection of the first metal layer on the substrate is at least partially overlapped with the vertical projection of the second metal layer on the substrate, and at least one groove is formed in each of the two sides of the second metal layer in the second direction; the liquid crystal orientation layer covers the display area and the non-display area, at least part of the area, on the side, away f