Laser　quenching　can　achieve　surface　hardening　with　narrow　heat　affected　zone　while　without　affecting　the　surface　roughness　of　the　material.　Therefore,　the　laser　quenching　technique　is　increasingly　applied　for　surface　hardening　in　key　components　such　as　precision　gear,　guide　rail,　etc.　Phase　transformation　and　thermal　diffusion　occur　in　the　process　of　laser　quenching,　resulting　in　change　of　microstructures　and　residual　stress　distribution　in　the　surface　layer　material.　To　evaluate　the　quality　of　the　laser-hardened　material　of　45and　30Cr　steel,　eddy　current　mapping　technology　is　employed　in　this　study　to　characterize　the　residual　stress　and　surface　hardness.　First,　C-scan　eddy　current　inspection　was　performed　to　the　laser　hardened　region.　The　mapping　results　of　the　impedance　parameters　clearly　show　the　boundary　between　the　hardened　zone　and　the　matrix.　Second,　X-ray　diffraction　system　and　Vickers　hardness　tester　were　alternatively　used　to　analyze　the　distribution　of　surface　hardness　and　residual　stress.　Third,　the　correlation　between　the　individual　eddy　current　parameter　and　the　surface　hardness　(or　residual　stress)　is　investigated　by　simple　linear　regression　tool.　The　impedance　amplitude　demonstrates　good　linear　dependencies　on　both　the　surface　hardness　and　residual　stress.　Therefore,　the　proposed　eddy　current　mapping　technology　is　capable　of　mapping　the　distribution　of　surface　hardness　(related　with　microstructures)　or　the　residual　stress　in　laser　hardened　ferromagnetic　components.　©　Published　under　licence　by　IOP　Publishing　Ltd.