Future　aerospace　vehicle　requires　a　fast　propellant　fueling　and　a　rapid　launching.　In　the　present　study,　a　high-pressure　chilldown　test　platform　is　established,　and　two　different　tube　structures,　including　a　straight　tube　and　an　interior　micro-fin　tube,　are　tested　under　different　inlet　Reynolds　number　(Re)　conditions.　The　test　results　show　that　for　a　typical　chilldown　case　through　the　straight　tube,　different　boiling　mechanisms　successively　dominate　the　fluid-wall　heat　transfer,　and　inverse　annular　flow　film　boiling　occupies　the　maximum　proportion　of　wall　temperature　decrease.　Increasing　inlet　flow　rate　could　accelerate　the　chilldown　rate,　and　the　time　cost　in　Re=45,000　case　is　only　about　15%　of　that　in　Re=5,000　case.　For　the　proposed　interior　micro-fin　tube,　the　test　results　verify　its　excellent　performance　in　improving　chilldown　rate.　Under　Re=5,000　condition,　the　time　cost　for　micro-fin　tube　case　is　only　about　70　s,　which　is　far　less　than　the　time　cost　by　a　straight　tube　case.　This　astonishing　performance　is　mainly　because　the　micro-fin　structure　induces　a　radial　velocity　component　in　the　inverse　annular　vapor　film.　The　radial　velocity　strike　acts　on　the　liquid-vapor　interface,　yielding　an　interface　fluctuation　or　even　a　liquid　column　breakup.　Therefore,　the　liquid　phase　could　contact　the　tube　warm　wall　earlier,　and　then　a　sustained　high　heat　flux　gives　rise　to　significant　temperature　decrease　effect　throughout　the　whole　chilldown　process.　©　2021