In　order　to　obtain　the　heat　release　law　of　nano　molten　salt　in　a　single　tank　system　with　submerged　heat　exchanger,　SiO2　nanoparticles　were　added　to　the　quaternary　mixed　nitrate,　and　the　effects　of　adding　nanoparticles　on　the　thermal　storage　and　heat　release　performance　of　a　single　tank　system　were　analyzed　experimentally.　The　results　show　that　the　addition　of　nanoparticles　can　improve　the　fluidity　of　molten　salt.　The　time　required　for　the　uniform　temperature　in　the　molten　salt　tank　during　the　heat　storage　process　is　shortened　by　17.9%.　The　process　of　heat　release　delays　the　rapid　decrease　of　salt　temperature　near　the　heat　exchanger　and　strengthens　the　convective　heat　transfer　ability　of　molten　salt.　The　addition　of　nanoparticles　extended　the　effective　heat　release　time　of　the　single-tank　heat　storage　system　by　16%　and　increased　the　cumulative　heat　release　by　13.8%.　This　study　will　provide　theoretical　basis　for　the　application　of　nano　molten　salt　in　heat　storage　system　and　the　optimization　of　single　tank　heat　storage　system.　©　2021,　Solar　Energy　Periodical　Office　Co.,　Ltd.　All　right　reserved.