The invention relates to a
deep sea sonar, which comprises a shell, a
transducer module and an elastic module, the side wall of the shell is provided with a first mounting hole and a second mounting hole, the
transducer module is arranged at the first mounting hole, the elastic module is arranged at the second mounting hole, and the
transducer module is connected with the elastic module. A
pressure balance cavity is defined by the shell, the transducer module and the elastic module, and the
pressure balance cavity is filled with a compressible fluid medium; the elastic module comprises a first elastic layer, a
rope net and a second elastic layer, the
rope net is adhered between the first elastic layer and the second elastic layer, a part of the first elastic layer and a part of the second elastic layer are filled in meshes of the
rope net, the rope net comprises a plurality of tensile ropes, and the tensile ropes are connected with the first elastic layer and the second elastic layer. The elongation of the tensile rope is smaller than that of the first elastic layer and that of the second elastic layer.