The　configuration　of　traditional　magnetic　Barkhausen　noise　(MBN)　sensor　employing　straight　barrel　type　of　ferrite　core　and　the　coupling　between　the　ferrite　core　and　the　material　surface　were　improved　to　be　suitable　for　curved　surface.Finite　element　simulation　method　was　used　to　compare　the　magnetization　efficiencies　of　three　types　(straight　barrel　type,　side　convex　type　and　inner　convex　type)　of　ferrite　core　structures.The　results　show　that　the　inner　convex　type　ferrite　core　was　the　best　among　the　three　types　of　core　structures.MBN　sensor　with　inner　convex　type　ferrite　core　was　fabricated　based　on　the　conclusions　obtained　from　finite　element　simulations.Experimental　tests　were　carried　out　on　steel　shafts　of　45　steel　and　different　radiuses.The　effect　of　the　radius　of　the　shaft　on　the　MBN　signal　amplitude　is　investigated.It　was　found　that　as　the　radius　gradually　increased　from　20mm　to　50mm,　the　MBN　signal　amplitude　successively　decreases,　which　was　mainly　caused　by　the　curvature　variation-induced　fluctuation　of　the　magnetic　field　in　the　tested　shaft.This　indicated　that　if　the　MBN　sensor　proposed　in　this　study　was　applied　for　curved　surface　detection,　it　was　better　to　employ　feedback　control　circuit　for　providing　stable　magnetic　field　for　material　magnetization.　©　2020,　The　Editorial　Board　of　Journal　of　Basic　Science　and　Engineering.　All　right　reserved.