Hydrogen　energy　has　quietly　become　the　key　to　dealing　with　various　environmental　problems　and　energy　transformation.　With　the　development　of　the　hydrogen　energy　industry,　safety　problems　caused　by　hydrogen　leakage　also　occur　continuously.　It　is　particularly　important　to　find　a　safe　and　reliable　visualization　technology　to　detect　hydrogen　leakage.　Some　issues　about　background　oriented　schlieren　and　laser　beam　profile　deformation　in　visualizing　and　diagnosing　flow　fields　are　summed　up　and　studied　both　theoretically　and　experimentally.　The　two　optical　methods　are　compared　from　two　aspects　of　flow　field　structure　visualization　and　parameter　diagnosis.　On　this　basis,　the　feasibility　of　combining　the　background　oriented　schlieren　with　the　laser　beam　profile　deformation　method　to　visualize　and　diagnose　the　flow　field　is　proposed,　and　an　experimental　device　is　established.　In　addition,　the　hydrogen　flow　field　is　selected　as　an　empirical　example.　The　experimental　results　show　that　the　combination　of　background　oriented　schlieren　and　the　laser　beam　profile　deformation　method　may　be　a　reasonable　and　feasible　means　for　complex　flow　field　structure　visualization　and　parameter　diagnosis.　©　2023　SPIE.