The application discloses a wire breakage detecting device of a displacement sensor. The output voltages of two secondary coils of the displacement sensor are superposed through an adding device; and then, a direct-current component signal in the output voltage of the adding device is extracted by utilizing a direct-current component conditioning circuit; an alternating-current component signal in the output voltage of the adding device is extracted by utilizing an alternating-current component conditioning circuit; the direct-current component signal is compared with a first preset voltage to judge whether the secondary coils are subjected to wire breakage or not; and the alternating-current component signal is compared with a second preset voltage to judge whether a primary coil is subjected to the wire breakage or not, so as to judge whether the displacement sensor is subjected to the wire breakage or not through a logic judging circuit. Through the output voltage of the adding device, whether the secondary coils or the primary coil are/is subjected to the wire breakage or not can be detected by utilizing one set of detection circuit, so as to greatly decrease the complexity of the wire breakage detecting device of the displacement sensor. Furthermore, the detection result of the logic judging circuit is output by adopting a digital quantity form, and the display of the detection result is intuitive.