The　international　energy　technology　revolution　is　considered　as　the　main　way　of　reducing　carbon　emissions,　and　most　countries　in　the　world　have　been　or　are　formulating　carbon　neutral　plan.　Hydrogen　energy　has　multiple　advantages,　such　as　source　variety,　high　energy　density,　terminal　zero　row,　and　wide　range　of　use.　It　is　of　great　significance　in　protecting　national　energy　security,　improving　the　atmospheric　environment　quality,　and　promoting　energy　industrial　upgrading.　This　paper　reviewed　optical　sensing　technologies　for　hydrogen　leak　detection,　including　tunable　semiconductor　laser　absorption　spectroscopy　technology　and　palladium-based　optical　fiber　sensing　technology.　Tunable　absorption　spectroscopy　technology　introduced　the　basic　principles　of　semiconductor　laser　wavelength　scanning　and　modulation,　spectral　absorption,　second　harmonic　signal　acquisition　and　gas　concentration　measurement;　taking　the　latest　hydrogen　detection　technology　as　an　example,　discussed　the　impact　of　environmental　background　absorption　spectra,　the　selection　principle　of　target　gas　fingerprint　spectrum　and　the　selection　principle　of　tunable　semiconductor　laser;　and　obtained　the　prototype　structure,　module　unit,　test　process　and　test　result　of　the　intelligent　tunable　semiconductor　laser　absorption　spectrum　gas　concentration　detector　developed　by　ourselves.　Palladium-based　optical　fiber　sensing　technology　briefly　described　the　sensing　mechanism　of　metal　palladium　to　hydrogen　and　the　thermodynamic　properties　of　sensing　materials;　introduced　the　structure,　measurement　principle,　and　measurement　principle　of　various　phase　modulation,　intensity　modulation　and　wavelength　modulation　optical　fiber　sensors;　discussed　the　development　process　of　various　palladium-based　optical　fiber　sensors;　and　briefly　analyzed　the　relationship　between　the　sensor＇s　macroscopic　performance　and　microscopic　mechanism.　Optical　detection　is　non-contact,　in　line　with　the　safety　requirements　of　hydrogen　detection,　and　has　the　characteristics　of　strong　selectivity,　high　sensitivity,　and　fast　response　speed.　©　2022,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.