This application provides an adaptive damping magnetic field sensor, including: a receiving coil, an adaptive damping matching resistance circuit, and an amplifying circuit; where the receiving coil is used for receiving an earth response signal generated by the earth under excitation of an emission source, and generating an induced voltage; the adaptive damping matching resistance circuit is used for receiving the induced voltage generated by the receiving coil and automatically matching a damping resistance value to obtain a near-source broadband observation signal; and the amplifying circuit is used for amplifying the observation signal with a constant gain and outputting a sensor output signal. This application carries out automatic matching control on the damping resistance value through the adaptive damping matching resistance circuit, thereby ensuring that the sensor can stably and reliably implement fine observation of an earth response under near-source, broadband and complex scene conditions.