Abstract: A quick-release coupling includes a socket defining a first passage in a connection port thereof, a locking member mounted in a front end of the socket and adapted for locking an inserted external male mating connector, an air valve control device mounted in a rear end of the socket, and a leak-proof device having a stopper mounted in the front end of the socket and defining therein a second passage, which is kept in communication with the first passage upon insertion of an external mating male connector into the front end of the socket to move the stopper backward, or blocked from the first passage after removable of the inserted external mating male connector and a forward movement of the stopper by the air valve control device.