Multi-layered complex aerospace structures demand advanced non-destructive testing technology. Traditional infrared thermal imaging in testing often blurs edges due to thermal diffusion, hindering precise defect edge detection. Current research on eddy current thermography primarily aims to enhance “hot spots” caused by eddy current accumulation at defect endpoints, yet underutilizes electric and thermal field data for defect contour reconstruction. This study analyzes the coupling between electric and thermal fields in eddy current thermography, developing efficient conversion and iterative reconstruction models. Accurately inverting wave signals from thermal and electric fields under alternating currents reveals the complete surface morphology of the test piece, offering novel solutions and methods for quantitative detection and performance evaluation of early damage in aerospace materials and processes.