The invention discloses a punching device for belt machining. The punching device comprises a base plate, a support, a workbench, a cross groove, a compressing device, a threaded rod, a movable block,a first installing plate, a telescopic rod, a second installing plate, a second spring, a first motor, a cam, an installing rod, an annular blade, a second motor, an adjusting rod, a sleeve, a connecting rod, a rack, a gear, an inner ratchet, a pawl and a fourth spring. The compressing device comprises a hinge pin, a first spring, a magnet and an iron plate. The punching device is provided with the workbench, the compressing device, a gas pipe and a dust collector, a belt is fixed, operation is simple, and convenience and quickness are achieved. The movable block, the threaded rod, the firstmotor, the cam, the annular cutter, the second motor, the adjusting rod, the sleeve, the connecting rod, the rack, the gear, an inner gear and the pawl are arranged and matched, continuous punching can be conducted at equal intervals, work efficiency is high, in addition, the hole space can be adjusted by adjusting the relative position of the sleeve and the adjusting rod, so that different needsare met, and applicability is high.