A vacuum suction structure of ankle joint and support barrel of artificial limb is connected, to the top thereof, with an artificial limb and the support barrel and is connected, to the bottom thereof, with an artificial foot. An ankle pressure cylinder forms therein an air chamber receiving therein an air chamber piston that forms therein a hydraulic fluid compartment. A hydraulic fluid supplementing cylinder and a one-way hydraulic fluid cylinder are arranged at one side of the ankle pressure cylinder and are connected via a connection piping system to the hydraulic fluid compartment. The one-way hydraulic fluid cylinder receives therein a push rod and the hydraulic fluid cylinder piston. When the structure is put into operation to allow a user to step forwards, the ankle pressure cylinder can provide both functions of hydraulic cushioning and air pressure regulation.
