The invention provides a compound type pressurizing oil cylinder. The compound type pressurizing oil cylinder comprises a piston rod assembly, the piston rod assembly comprises an inner rod and an external piston rod arranged on the inner rod in a sleeving mode, medium-pressure oil enters a medium-pressure oil port and enters a medium-pressure oil cavity through a medium-pressure oil way passageway formed by the axis of the inner rod, and then the external piston rod is pushed to advance by a first preset stroke. After the first preset stroke is completed, high-pressure oil enters a high-pressure oil cavity through a high-pressure oil port, directly acts on a piston and pushes the piston to advance, and therefore the external piston rod continues to advance by a second preset stroke; and meanwhile, the medium-pressure oil cavity keeps continuous input of medium-pressure oil, and the die assembly pressure is medium pressure plus high pressure. After die assembly is completed, the process is switched to oil return, medium pressure and high pressure are cut off, back-pressure oil is provided for a back-pressure oil port, and therefore resetting, namely descending resetting of the oilcylinder, of the first preset stroke and the second preset stroke is achieved. The compound pressurizing oil cylinder has the effects of reducing energy consumption, improving the stability of the oilcylinder, reducing the pressure of the oil cylinder in a high-pressure state and the like.