Molten　salt　is　a　major　heat　storage　medium　for　medium-high　temperature　solar　thermal　power　applications.　The　heat　storage　density　and　heat　transfer　efficiency　of　molten　salt　are　important　factors　of　solar　thermal　power　efficiency.　Recently,　many　studies　have　reported　that　molten　salt　nanofluid,　which　is　formed　by　adding　nanoparticles　in　molten　salt,　can　remarkably　enhance　the　specific　heat　capacity　of　molten　salt.　However,　research　on　the　forced　convection　heat　transfer　of　molten　salt　nanofluid　is　inadequate.　In　this　study,　the　forced　convection　heat　transfer　experiments　were　carried　out　in　a　circular　tube　of　a　previously　reported　promising　molten　salt　nanofluid　composed　of　KNO3-Ca(NO3)(2)　+　1　wt%　of　20　nm　SiO2　nanoparticles　(K-C-S-nm).　Results　showed　that　compared　with　its　base　pure　molten　salt,　the　K-C-S-nm　molten　salt　nanofluid　exhibited　substantially　better　forced　convection　heat　transfer　performance　under　the　same　working　condition.　The　Nusselt　number　and　the　convective　heat　transfer　coefficient　of　K-C-S-nm　molten　salt　nanofluid　were　16.3%　and　39.9%　higher　than　its　base　pure　molten　salt,　respectively.　The　experimental　data　of　K-C-S-nm　molten　salt　nanofluid　largely　differed　from　the　classical　correlation　equations.　Hence,　a　new　empirical　heat　transfer　correlation　equation　was　set　for　K-C-S-nm　molten　salt　nanofluid,　and　the　deviation　between　the　experiment　data　and　new　correlation　was　within　+/-　7%.