Liquid　jet　quenching　is　widely　used　in　steel　heat　treatment　process　in　order　to　obtain　specific　enhanced　material　properties　by　controlling　the　heat　transfer　performance.　The　hardness　and　properties　of　metal　material　are　influenced　by　spatial　and　temporal　heat　transfer　behavior.　In　this　work,　the　heat　transfer　characteristics　between　molten　salt　nanofluids　and　high　temperature　metal　steel,　the　temperature　field　inside　steel,　and　the　phase　structure　field　in　the　cooling　process　of　molten　salt　nanofluids　jet　impingement　steel　are　numerically　studied.　The　different　jet　conditions　such　as　temperature,　speed,　and　angle　are　studied　based　on　multi　physics　field　coupling　method.　The　maximum　phase　formation　rate　of　pearlite　decreases　with　increasing　temperature.　When　the　jet　temperature　of　molten　salt　nanofluids　is　450　degrees　C,　the　final　phase　content　of　bainite　is　4.72%.　Compared　with　jet　temperature　450　degrees　C,　the　final　bainite　phase　content　at　400　degrees　C　and　350　degrees　C　increased　by　30.5%　and　73.9%,　respectively.　The　angle　of　molten　salt　nanofluids　jet　has　a　significant　impact　on　the　cooling　rate　of　steel　during　the　heat　treatment　process.　When　the　jet　angle　is　30　degrees,　the　average　pearlite　formation　rate　curve　of　the　steel　plate　is　similar　to　the　superposition　of　two　different　＂bell＂-shaped　curves,　resulting　in　a　double　peak　value.　This　work　could　provide　theoretical　support　for　jet　impingement　heat　treatment　of　molten　salt　nanofluids　to　metal　steel.