Abstract: Pulsed Eddy Current Testing(PECT) is an effective Electromagnetic Nondestructive Evaluation(ENDE) technique for quantitative evaluation regarding the integrity of multi-layer conductors. Conventional PECT utilizes induction coils and solid-state magnetic field sensors which give the transient signals of net magnetic field for defect detection, classification and characterization. In this paper, we introduce Gradient Magnetic Field Measurement(GMFM), which has been intensively used in Magnetic Resonance Imaging(MRI), to PECT in an effort to improve the PECT sensitivity to multi-layer conductors. The closed-form expressions of GMFM-based PECT signals have been formulated via the Extended Truncated Region Eigenfunction Expression(ETREE) modeling. Through theoretical and experimental investigation, it is found that the proposed GMFM-based PECT is significantly advantageous over traditional PECT in terms of high detection-and-evaluation sensitivity to subsurface material degradation of multi-layer conductors.