As　the　world＇s　energy　demand　continues　to　grow　and　the　environmental　pollution　problem　caused　by　fossil　energy　sources　becomes　more　and　more　serious,　the　hydrogen-electric　coupling　system　is　considered　a　highly　competitive　new　energy　supply　method　in　the　future.　A　unique　Background　Oriented　Schlieren　(BOS)　technique　is　proposed　to　detect　hydrogen　leakage　in　the　low　and　high　power　consumption　peaks.　Firstly,　the　principle　of　the　BOS　is　analyzed,　and　a　new　inverse　function　of　gas　jet　concentration　distribution　is　proposed;　secondly,　a　BOS　optical　experiment　system　is　built,　and　the　displacements　of　background　particles　at　z　=　10d,　20d　and　30d　at　three　axial　positions　are　obtained,　and　the　formed　undesirable　displacement　function　is　corrected　by　laser　beam　profile　deformation　technique,　and　the　radial　concentration　distribution　curves　at　three　axial　positions　are　obtained　by　concentration　inversion.　Comparing　the　concentration　distribution　curves　obtained　after　the　correction　with　those　obtained　from　CFD　simulation　and　uncorrected　BOS　experiments,　it　was　found　that　after　the　correction,　the　concentration　distribution　curves　of　BOS　were　closer　to　the　simulation　results　and　could　reflect　the　radial　concentration　distribution　of　hydrogen　more　accurately.　We　also　find　that　the　average　expansion　angle　of　the　hydrogen　jet　is　about　23°　for　different　combinations　of　outlet　pressure　and　tube　diameter,　which　is　very　similar　to　the　theoretical　and　experimental　studies.　The　hydrogen　monitoring　system　based　on　BOS　technology　is　a　simple　device　with　low　cost,　high　sensitivity,　fast　response,　and　high　reliability,　which　provides　a　new　idea　and　method　for　hydrogen　leak　monitoring　in　a　hydrogen-electric　coupled　system.　©　2023　The　Institution　of　Chemical　Engineers