The invention discloses a double-side stepping printer, and the printer comprises two printing devices, one paper conveying device, one printing control computer board, one paper loading and unloading part, and one case. The printer mainly controls the two printing devices, which are arranged together in parallel, to step and carry out printing through the printing control computer board which is design and programed newly, thereby enabling the later printing device to trigger a printing command once paper extending out of the former printing device in printing enters the later printing device so as to print the back of the paper, and achieving a purpose that two printing devices can carry out stepping according to the odd-even sequence and carry out continuous printing. The printing mode can reduce a big time interval when a conventional two-side printer respectively prints two sides of paper, and enables the printing efficiency to be higher.