The motivation of this paper is to identify the variation of stress filed in multi-strand tendon anchorage system using electromechanical impedance measurement. To achieve the objective, the following approaches are implemented. Firstly, stress variation in multi-strand anchorage system due to strand breakage is analyzed to determine the location of impedance acquisition. Secondly, a piezoelectric-based interface technique is designed to localize the damage strand. Lastly, the conceptual design of the PZT-interface is preliminarily verified by an experimental test. Impedance signatures obtained from PZT-interface are quantified by using RMSD index (root-mean-square-deviation). The result shows that the PZT-interface technique is promisingly to identify damage strands.