The printing unit of stacked flexo printing machine is stacked up and down, Arranged on one or both sides of the main wall panel of the printed parts, Each printing color group is driven by gears mounted on the main wall panel. When printing, the substrate passes through each printing color unit in turn, Complete all printing. Each printing color group has an impression cylinder, Plate cylinder, and inking device, And the structure of each printing color group is the same. The stacked flexographic printing machine can print 1-8 colors, But mostly 6 colors. If equipped with a reversing device, it can also print on both sides.