The　minimal　lattice　changes　caused　by　thermal　ageing　present　a　significant　challenge　for　non-destructive　testing.　This　study　proposes　the　use　of　a　high-frequency　resonance　eddy　current　sensor　and　a　multi-physical　field　fusion　method　to　address　this　issue.　Initially,　high-frequency　resonance　technology　is　employed,　whereby　not　only　is　an　eddy　current　secondary　magnetic　field　generated,　but　also　an　electric　field　in　the　gap　between　the　planar　coil　and　the　metal.　Therefore,　the　excitation　of　a　multi-physical　field　in　eddy　current　sensors　has　been　achieved.　Secondly,　a　probe　multi-parameter　separation　algorithm　is　proposed.　Consequently,　the　separation　of　the　magnetic　and　electric　fields　can　be　achieved.　The　results　of　experiments　conducted　on　12CrMoV　steel　demonstrate　that　the　parameter　capacitance　relating　to　electric　fields　is　more　accurate　and　linear　than　the　parameters　resistance　and　inductance　relating　to　eddy　current　secondary　magnetic　fields.　Finally,　the　multi-parameter　and　multi-physical　field　fusion　method　is　discussed　in　order　to　enhance　the　accuracy　of　thermal　ageing　characterization.　The　results　of　the　experiments　demonstrate　that　the　fusion　characterization　method,　which　combines　resistance　and　capacitance,　leads　to　a　significant　reduction　in　error,　by　as　much　as　80%,　when　applied　to　the　characterization　of　eddy　current　magnetic　fields　and　gap　electric　fields.　　©　2001-2012　IEEE.