A vacuum suction and pressure regulation cylinder includes a pneumatic cylinder, in which a fixed division plate is arranged. A piston assembly is slidably arranged in the fixed division plate and includes an airtight piston mounted to a middle portion thereof and including a flowrate regulation screw and an end of the piston assembly is provided with a second airtight piston so as to define, in an interior space of the pneumatic cylinder, a first air chamber, a second air chamber, and a third air chamber, which are in communication with a prosthesis sleeve. When the piston assembly moves, air flow induced in the pneumatic cylinder varies the sizes of the air chambers for regulation of the spaces thereof Further, the variation of the air chambers helps evacuate the sleeve so as to make a stump and the prosthesis tightly coupled to each other through suction.
