Harmonic　eddy　current　magnetic　field　inspection,　as　one　of　pipeline　nondestructive　inspection　technology,　can　be　accurately　and　efficiently　used　to　estimate　the　damage　of　buried　steel　pipeline.　Based　on　the　principle　of　harmonic　eddy　current　magnetic　field　detection,　a　theory　model　of　double　frequencies　alternating　excitation　was　established,　and　a　non-contact　coil　array　detection　probe　was　also　designed.　An　indoor　experimental　platform　was　built　to　proceed　experimental　study　on　the　differences　in　magnetic　induction　intensity　distribution　for　various　pipeline　defect　species,　and　the　variation　in　magnetic　induction　intensity　for　different　excitation　frequencies　and　input　voltages.　Results　showed　that　change　in　resistivity　due　to　the　pipeline　defect　causes　a　nonuniform　current　distribution　that　distorts　the　induced　magnetic　field,　resulting　significant　increase　in　the　magnetic　induction　intensity;　While　moving　the　probe　along　the　surface　of　the　pipeline,　better　detection　results　can　be　achieved　for　various　defect　species　with　greater　defect　depth　and　smaller　angular　orientation　between　defect　trend　and　moving　direction;　Similarly　a　robust　change　in　the　magnetic　induction　intensity　can　be　observed　with　low　signal　frequency　of　harmonic　power　supply　and　greater　input　voltage　of　detection　probe.　The　researches　done　prove　that　harmonic　eddy　current　magnetic　field　inspection　can　effectively　realize　the　nondestructive　damage　detection　of　buried　steel　pipeline.　©　2018　IET　Conference　Publications.　All　rights　reserved.