The invention discloses an all-in-one machine for combing and lengthening plates. The all-in-one machine comprises a rack, a feeding mechanism arranged on the rack, a front pressing-down moving assembly, a combing-tooth glue spraying assembly, a rear pressing-down fixing assembly and a discharging mechanism. The front downward-pressing moving assembly comprises a moving platform and a front downward-pressing plate, the front downward-pressing plate moves up and down under the action of a front downward-pressing power mechanism, and the moving platform moves front and back under the action of a platform power mechanism; the comb tooth glue spraying assembly comprises a comb tooth head, a front comb tooth cutter group, a rear comb tooth cutter group and a glue spraying mechanism; the rear downward pressing fixing assembly comprises a fixing platform and a rear downward pressing plate, and the rear downward pressing plate moves up and down under the action of a rear downward pressing power mechanism. The device is simple and compact in structure and convenient to operate, conveying of a middle conveying line is omitted, the occupied space is small, comb teeth, glue spraying and lengthening are the same standard, the lengthening quality of plates is guaranteed, the cost of plate raw materials is reduced, the machining efficiency of products is greatly improved, and the labor intensity of workers is reduced.