Embodiments of the present disclosure relate to the field of medical instrument, in particular to a sensor device applied in an articulation and an artificial limb system to improve control precision of the sensor. The sensor device of the present disclosure includes a plurality of magnets spaced apart from each other, the adjacent magnets having opposite polarities in a moving direction of the articulation； and at least one magnetic inductor for monitoring a displacement of the magnets caused by movement of the articulation.
