Abstract: Stratified metallic structures are widely used in various industries such as petroleum, chemical, aerospace and energy fields. Subsurface Material Degradation(SMD) occurs within the structures due to rigorous working environment, which influences the operation of crucial components in the large-scale complex apparatus. In this paper, a new Lift-off Intersection Point(LOI) has been discovered via theoretical study of Pulsed Eddy Current technique(PEC). Based on the investigation of the characteristics of the new LOI, a method for evaluation of SMD in stratified metallic structures has been proposed. The method extends the PEC application currently only for evaluation of surface material degradation. Through numerical simulations, the validity and practicability of the proposed method have been investigated.