The invention relates to a method for testing the underwater plugging-unplugging performance of an underwater wet type connector. The method comprises: S1, an underwater wet type connector plug is fixed at a front clamp and an underwater wet type connector socket is fixed at a rear clamp; S2, cables of the underwater wet type connector plug and the underwater wet type connector socket are connected with an external testing device; S3, a motor assembly is started and drives the front clamp to drive the underwater wet type connector plug and the underwater wet type connector socket to be plugged; S4, according to a display result of the external testing device, the performance of the underwater wet type connector is determined; and S5, the motor assembly is turned off and testing is ended. According to the invention, the front clamp and the rear clamp are installed in the water tank to connect the connector plug and the connector socket respectively and fixedly and thus the connector performance is tested in an underwater state, so that the accuracy of the underwater wet type connector is improved; the cables of the plug and the socket are led out respectively and are connected withindicator lamps and the connector performance is determined by observing the on-off situation of display lamps.