The invention provides a compaction roller of a printing machine. The compaction roller of the printing machine belongs to the field of a mechanical technology, and solves the technical problems thatan existing printing machine is poorer in printing quality and the like. The printing machine comprises a case, and an unwinding roller and a winding roller rotatably connected into the case; a printing roller is rotatably connected between the unwinding roller and the winding roller in the case; the compaction roller is arranged in the case and located right below the printing roller; the compaction roller comprises an inner roller with an annular cross section and an outer roller with an annular cross section; the inner roller and the outer roller are fixed through a plurality of fixing rodsdistributed radially; two ends of the inner roller are rotatably connected with the shell; an annular cylindrical air inflation pressure sleeve sleeves outside the outer roller and is fixed with theouter roller; and the air inflation pressure sleeve is made of elastic materials, and can press close to the lower side face of the printing roller after being inflated. The compaction roller of the printing machine provided by the invention has the advantage of improving the printing quality.