Molten　nitrates　have　been　considered　as　attractive　heat　transfer　and　storage　materials　in　concentrated　solar　power　(CSP).　In　this　paper,　thermophysical　parameters　such　as　density,　specific　heat,　viscosity　and　thermal　conductivity　of　binary　NaNO3-KNO3　with　different　Na　+　concentrations　were　calculated　within　the　range　of　600–800　K.　The　simulated　values　of　thermophysical　properties　closely　matched　the　experimental　values.　Particularly,　the　reverse　non　-　equilibrium　molecular　dynamics　(RNEMD)　approach　was　employed　to　determine　viscosity　and　thermal　conductivity.　The　deviation　of　calculated　thermal　conductivity　for　Solar　salt　from　the　experimental　value　is　less　than　1　%　with　higher　prediction　accuracy.　The　average　deviation　of　the　simulated　value　of　the　viscosity　from　the　experimental　value　is　only　3.1　%　in　the　temperature　range　of　500–700　K.　The　microscopic　mechanisms　of　composition/temperature　for　macroscopic　properties　were　elucidated　from　the　local　structure.　An　increase　in　temperature　enhances　the　thermal　motion　of　the　ions　and　the　system　becomes　loose,　thereby　causing　a　reduction　in　the　density,　viscosity　and　thermal　conductivity　of　the　system.　As　Na+　concentration　rises,　the　bond　lengths　of　N-O　and　N-N　decrease,　the　structure　of　NO3−　collapses,　the　system　becomes　more　compact　and　the　heat　transfer　distance　is　reduced,　leading　to　an　increase　in　density　and　thermal　conductivity.　Additionally,　there　is　an　enhancement　of　NO3−　intramolecular　interactions,　which　consequently　results　in　an　increase　in　the　specific　heat　capacity.　The　diffusion　activation　energy　and　viscous　activation　energy　are　maximum　in　the　system　with　64　%　Na+　concentration,　indicating　the　lower　mobility　of　the　system　at　this　composition.　©　2025