The invention belongs to the technical field of information measurement, and discloses an eddy current sensor for simultaneously measuring the displacement and thickness of a metal work piece. The eddy current sensor includes a main control component, a closed-loop current amplifier and a probe. The closed-loop current amplifier is electrically connected with the main control component and the probe. The main control component is used for generating an excitation signal which consists of a high-frequency signal and/or a low-frequency signal. The probe includes a probe shell, an excitation coil accommodated in the probe shell, and magnetic sensors arranged below the excitation coil. The excitation coil is electrically connected to the closed-loop current amplifier. The magnetic sensors are used for simultaneously sensing a magnetic field generated by the excitation coil and a magnetic field generated by eddy current. The invention further relates to a method for simultaneously measuring the displacement and thickness of a metal work piece. Displacement and thickness are measured simultaneously through a specific excitation signal. The method is simple and easy to implement. The eddy current sensor and the method have high flexibility and a wide application range.