With　the　continuous　increase　in　energy　demand,　the　exploration　and　research　of　new　energy　sources　are　becoming　increasingly　important.　Molten　salt　nanofluids　as　solar　thermal　conversion　heat　transfer　and　storage　media　are　gradually　becoming　widespread.　To　futher　enhance　the　influence　of　types　and　concentrations　of　multiwalled　carbon　nanotubes　(MWCNTS)　on　the　thermal　properties　of　Solar　and　Hitec　salt,　short　multi-walled　carbon　nanotubes　(S-MWCNTS),　MWCNTS,　and　carboxylated　carbon　nanotubes　(COOH-MWCNTS)　with　the　same　size　but　different　types　were　used　as　additives　to　prepare　molten　salt　nanofluids.　Specific　heat　(Cp),　thermal　conductivity,　and　other　parameters　were　experimentally　measured　and　analyzed.　The　results　demonstrated　that　the　addition　of　0.5　wt%　S-MWCNTS　resulted　in　the　most　significant　enhancement　in　Cp　and　thermal　conductivity,　with　an　increase　of　13.79　%　and　78.18　%　compared　to　Solar　salt,　and　an　increase　of　21.13　%　and　130.69　%　compared　to　Hitec　salt.　Scanning　electron　microscopy　(SEM)　observation　showed　that　the　molten　salt　nanofluid　containing　0.5　wt%　S-MWCNTS　and　COOH-MWCNTS　exhibited　a　densely　stacked　network　structure,　which　increased　its　surface　area.　Based　on　these　findings,　further　research　was　conducted　on　the　thermal　properties　of　SMWCNTS　nanoparticles　on　Solar　and　Hitec　salt　at　different　concentrations.　0.3　wt%　S-MWCNTS　resulted　in　the　most　significant　enhancement　in　Cp,　which　was　22.07　%　higher　than　Solar　salt　and　23.95　%　higher　than　Hitec　salt;　The　maximum　thermal　conductivity　improvement　of　adding　0.6　wt%　S-MWCNTS　to　Solar　salt　is　101.14　%,　and　the　maximum　thermal　conductivity　improvement　of　adding　0.5　wt%　S-MWCNTS　to　Hitec　salt　is　130.69　%.