The invention provides an underwater bi-pass communication device. A control unit is arranged in a water surface integrated operation tank; the water surface integrated operation tank and a control panel are arranged at the position of a diving supervisor; the control unit comprises a power circuit, a transmitting/receiving bi-pass circuit, a signal acquiring and amplifying circuit, a power amplifying circuit and a power monitoring circuit; level signals from two diver transmitters are transmitted to the signal acquiring and amplifying circuit and the power amplifying circuit to be processed through the transmitting/receiving bi-pass circuit; one path of level signal is transmitted to a loudspeaker on the control panel to be played after processing; and the other path of level signal is transmitted to the receiver between the divers for playing to realize bi-pass communication between the divers. Through adoption of the underwater bi-pass communication device, the aim of bi-pass communication among the underwater divers is fulfilled, and the diving supervisor can be in communication with the two divers on the water surface or underwater simultaneously or separately through controlof a PTT switch on the control panel or communication switches selected by the divers.