Underwater electric connector connecting structure and plugging method thereof

The invention relates to an underwater electric connector connecting structure and a plugging method thereof, a water pumping device is arranged on the peripheral wall of a centering shell, a water pumping port is formed in the centering shell, one end of the water pumping port is communicated with the water pumping device, and the other end of the water pumping port is communicated with a first rotating cavity; at least one buckle is arranged on the peripheral wall of the end, away from the water pumping device, of the centering shell. An annular gap matched with the centering shell is formed in the double-layer shell, and at least one guide groove is formed in the inner circumferential wall of the annular gap; when the buckle slides to a preset position of the guide groove, the plug and the socket jointly encircle the first rotating cavity into a sealing cavity, and the water pumping device pumps water from the sealing cavity through the water pumping opening, so that a vacuum environment is formed in the s