To　observe　the　effect　of　nanoparticle　on　the　thermal　physical　properties　of　the　low　melting　point　eutectic　mixed　nitrate　salt.　In　this　study　1%　(mass)　SiO2　nanoparticles　with　the　average　size　of　20　nm　were　doped　into　the　mixed　salt　[Ca(NO3)2•4H2O-KNO3-NaNO3-LiNO3]　to　obtain　molten-salt　nanocomposites　at　different　dispersion　condition　by　the　high　temperature　melting　dispersion　method.　Specific　heat　capacity　and　thermal　diffusivity　of　the　nanocomposites　were　analyzed　by　differential　scanning　calorimeter　(DSC)　and　laser　flash　apparatus　(LFA).　Then　the　thermal　conductivity　was　gotten.　The　results　show　that　at　the　stirring　rate　of　600　r/s　the　thermal　physical　properties　of　the　molten-salt　nanocomposites　vary　with　the　mixing　time　(15,　45,　90,　120　and　150　min).　At　the　mixing　time　of　45　min,　the　thermal　physical　properties　of　the　molten-salt　nanocomposites　reach　the　optimum　enhancement.　The　average　enhancement　of　the　specific　heat　capacity,　thermal　diffusivity　and　thermal　conductivity　was　11.5%,　12.9%,　and　26.4%,　respectively.　The　scanning　electron　microscope　(SEM)　found　that　a　large　number　of　special　nanostructures　(resembling　chain-like　nanostructures)　existed　on　the　surface　of　solid　molten-salt　nanocomposites.　The　special　nanostructures　with　large　specific　surface　area　and　high　surface　energy　may　enhance　the　specific　heat　capacity　and　thermal　conductivity　of　the　molten　salt　nanocomposites.　©　All　Right　Reserved.