Disclosed is a preparation method for an array substrate including: forming a first conductive portion on a substrate; sequentially forming a first insulating layer, a second insulating layer and a third insulating layer on the side of the first conductive portion that faces away from the substrate; forming, through one-time patterning process, a first sub-via that penetrates through the third insulating layer, the second insulating layer and a first part of the first insulating layer; forming a fourth insulating layer on the side of the third insulating layer that faces away from the substrate; etching and removing the fourth insulating layer and the first insulating layer of the second thickness that are at the first sub-via, so as to form a first via; and forming a first connection electrode on the side of the fourth insulating layer that faces away from the substrate.