Shield　tunneling　machines　are　widely　used　around　the　world　for　construction　in　tunnels,　railways,　and　subways.　The　bracket　of　a　shield　tunneling　machine,　which　is　welded　to　the　cutterhead,　is　prone　to　suffer　maximum　stress　due　to　its　bad　operating　environment.　This　paper　introduces　a　laser-generated　surface　acoustic　wave　for　non-destructive　detection.　A　numerical　model　is　constructed　to　analyze　the　interaction　between　a　laser-generated　surface　acoustic　wave　and　a　bracket　structure.　The　results　show　that　the　laser-generated　acoustic　wave　with　a　longitudinal　wave,　a　shear　wave,　and　a　Rayleigh　wave　can　propagate　along　the　surface　of　the　bracket　structure.　When　the　wave　encounters　the　junction　of　the　welding　and　the　horizontal　surface,　it　generates　a　reflected　wave,　a　transmitted　wave,　and　a　mode　converted　wave.　This　propagating　phenomenon　can　be　used　for　the　defect　detection　of　a　bracket　in　the　future.　©　2022　The　authors　and　IOS　Press.