The　corrosivity　of　molten　salt　can　be　detrimental　to　the　safe　operation　and　longevity　of　concentrated　solar　thermal　power　generation　equipment.　Additionally,　the　presence　of　impurity　Cl-　can　increase　corrosion　on　metal　materials,　leading　to　mechanical　property　degradation.　To　assess　the　extent　of　this　effect,　the　corrosion　behaviour　of　three　types　of　stainless　steel　(304,　316L,　and　347H)　in　molten　salt　at　high　temperatures　was　studied　using　the　loss-in-weight　method　and　tensile　tests.　According　to　the　findings,　the　Rdepths　of　304,　316L,　and　347H　stainless　steels　are　0.0018　mm/a,　0.0016　mm/a,　and　0.0019　mm/a,　respectively,　resulting　in　a　decrease　in　elongation　of　12.2%,　7.0%,　and　3.7%　after　720　h　of　corrosion　at　600　degrees　C.　Furthermore,　at　a　higher　temperature　of　680　degrees　C,　the　Rdepths　of　all　stainless　steels　increased,　and　the　elongation　decreased　by　25.4%,　18.9%,　and　13.5%,　respectively.　Similar　corrosion　behaviour　was　observed　in　347H　stainless　steel　with　increased　chloride　ion　concentration.　However,　the　yield　strength　and　tensile　strength　of　stainless　steel　did　not　exhibit　significant　changes　under　different　experimental　conditions.　The　corrosion　mechanism　of　metal　alloys　in　molten　salt　is　mainly　due　to　the　selective　corrosion　of　Cr　and　its　dissolution　into　molten　salt　in　the　form　of　ions.