To　apply　the　micro-magnetic　testing　method　to　the　induction　hardened　case　depth　evaluation,　an　integrated　sensor　was　designed　to　synchronously　detect　the　tangential　magnetic　field　strength　signal,　the　hysteresis　curves　and　the　Barkhausen　noise.　A　total　of　eight　features　or　parameters　were　extracted　from　the　above　mentioned　three　kinds　of　signals　for　induction　hardened　case　depth　characterization　in　steel　rods.　Stepwise　regression　method　was　employed　to　help　select　the　parameters　with　a　significant　level　lower　than　0.07.　Finally,　the　coercive　force　Hc,　the　amplitude　of　the　three　harmonics　(A3),　the　distortion　factor　(K)　of　tangential　magnetic　field　strength　signal,　and　the　parameter　Hcm　of　the　butterfly-like　Barkhausen　noise　envelop　were　selected　as　the　input　of　a　multivariable　linear　regression　model.　The　established　linear　regression　model　had　an　averaged　prediction　error　of　3.87%.　The　developed　experimental　set-up　together　with　the　signal　analysis　method　is　expected　to　be　applied　to　quantitative　measurement　of　the　induction　hardened　case　depth　in　rod-like　ferromagnetic　components.　©　2018,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.