A joint, comprising a male module and a female module capable of docking with each other, wherein the male module comprises a core rod and a sliding cylinder, and the sliding cylinder is slidably sleeved on an outer periphery of the core rod; a first valve port is disposed in the sliding cylinder, and the core rod is provided with a piston head that is in hermetic fit with the first valve port; the female module comprises a valve body and a piston; a first channel is disposed in the valve body, the piston is slidably disposed in the first channel, and a second valve port that is in hermetic fit with the piston is disposed in the first channel; and one end of the sliding cylinder is provided with a first docking port, the valve body is provided with a second docking port communicating with the first channel, and after the first docking port and the second docking port are docked hermetically, the core rod slides in a direction of extending from the first docking port, the piston head is separated from the first valve port, the core rod sliding pushes the piston to slide in a direction of retracting into the second docking port, and the piston is separated from the second valve port; characterized in that: the male module further comprises a first tightening spring, and wherein a first stopper is disposed on the core rod of the male module and a second stopper is disposed in the sliding cylinder of the male module; and the first tightening spring acts on the core rod and the sliding cylinder, and is configured to drive the core rod to slide in a direction of retracting into the first docking port so that the piston head is in hermetic contact with the first valve port and the first stopper abuts the second stopper to prevent the core rod from further sliding under the acting force of the first tightening spring. the male module comprises a core rod and a sliding cylinder, and the sliding cylinder is slidably sleeved on an outer periphery of the core rod; a first valve port is disposed in the sliding cylinder, and the core rod is provided with a piston head that is in hermetic fit with the first valve port; the female module comprises a valve body and a piston; a first channel is disposed in the valve body, the piston is slidably disposed in the first channel, and a second valve port that is in hermetic fit with the piston is disposed in the first channel; and one end of the sliding cylinder is provided with a first docking port, the valve body is provided with a second docking port communicating with the first channel, and after the first docking port and the second docking port are docked hermetically, the core rod slides in a direction of extending from the first docking port, the piston head is separated from the first valve port, the core rod sliding pushes the piston to slide in a direction of retracting into the second docking port, and the piston is separated from the second valve port; characterized in that: the male module further comprises a first tightening spring, and wherein a first stopper is disposed on the core rod of the male module and a second stopper is disposed in the sliding cylinder of the male module; and the first tightening spring acts on the core rod and the sliding cylinder, and is configured to drive the core rod to slide in a direction of retracting into the first docking port so that the piston head is in hermetic contact with the first valve port and the first stopper abuts the second stopper to prevent the core rod from further sliding under the acting force of the first tightening spring. the male module further comprises a first tightening spring, and wherein a first stopper is disposed on the core rod of the male module and a second stopper is disposed in the sliding cylinder of the male module; and the first tightening spring acts on the core rod and the sliding cylinder, and is configured to drive the core rod to slide in a direction of retracting into the first docking port so that the piston head is in hermetic contact with the first valve port and the first stopper abuts the second stopper to prevent the core rod from further sliding under the acting force of the first tightening spring.