The invention discloses an underwater optical fiber quick connector and the application thereof. The underwater optical fiber quick connector comprises a male joint and a female joint. The male joint comprises an installation joint (1) whose back end is provided with a first external screw thread (11). The female joint comprises a sleeve core (5). The back end of the sleeve core (5) is connected with a hosepipe (9) through a hold hoop (10). The front end inner side of the sleeve core (5) is provided with an optical fiber coupler (7). The front end outer side of the sleeve core (5) is provided with a connecting nut (4). The front end of the installation joint (1) is provided with a second external screw thread (12) in cooperation with the connecting nut (4). The quick connector of the invention can be manufactured at a low cost. With a compact structure, the joint installation space is reduced. In addition, due to the multi-layered sealing structure, the quick connector is safe and reliable in use. As the quick connector can be dismantled conveniently, the connection between fibers and the signal transmission become more convenient and rapid.