A roller train and a substrate conveying device are provided. The roller train is used for a substrate and includes a first roller including a first delimitation part, and a second roller including a second delimitation part. An axial line of the first roller is parallel to that of the second roller; the first roller and the second roller contact an upper surface and a lower surface of the substrate, respectively; and, the first delimitation part and the second delimitation part are arranged on the first axis and the second axis, respectively, and configured to delimit axial displacement of the first roller and the second roller, respectively. The first delimitation part and the second delimitation part cooperate to prevent misalignment between the first roller and the second roller.