The invention discloses a cylinder with a double self-locking structure. The cylinder with the double self-locking structure comprises a cylinder body. A rear end cover is arranged at the rear end ofthe cylinder body. A front end cover is arranged at the front end of the cylinder body, and a
handle is arranged at the position, located at the upper end of the front end cover, of the front end of the cylinder body. A
piston rod is arranged on the front surface of the front end cover. The cylinder with the double self-locking structure enables air pressure in an accommodating cavity and a firstouter
air cavity to be complementary to air pressure at the front end of an inner
piston, and the internal air pressure of the cylinder with the double self-locking structure is constant. When the inner
piston moves forward, the air pressure at the front end of the inner piston is pushed into the accommodating cavity and the first outer
air cavity, so that a
brake piston is just moved downward, abrake rod is pulled out of an embedded hole of the
piston rod surface, and a limiting rod is pushed upward, so that the inner piston is locked and limited, and when the inner piston retracts, the airpressure drives the
brake rod to be embedded into the embedded hole of the
piston rod, and meanwhile, the limiting rod is retracted downward, the limiting and locking of the inner piston is released,and the
brake rod is matched with the limiting rod, so that a double self-locking function for the cylinder is achieved.