Commercial　mixed　salt　generally　contains　the　impurity　chloride　ion　(Cl)　due　to　the　influence　of　the　preparation　process　of　the　single　component　salt　that　constitutes　the　mixed　salt.　The　impurity　Clcan　increase　the　corrosion　of　molten　salt　to　metal　materials.　In　order　to　investigate　the　effect　of　molten　salt　with　different　content　of　Cl　on　the　corrosion　of　metal　materials,　a　low　melting　point　quaternary　nitrate　and　solar　salt　were　selected　as　the　base　salt　to　analyze　the　corrosion　rule　of　Cl.　Using　the　weight　loss　method,　the　corrosion　behaviors　of　the　two　molten　nitrate　salts　with　and　without　Clto　316L　stainless　steel　were　studied.　The　results　of　the　corrosion　test　for　1000　h　show　that　the　quaternary　mixed　molten　salt　with　low　Clcontent　of　0.03　wt%　has　the　lowest　corrosion　rate　on　316L　stainless　steel　than　that　of　the　other　two　salts　with　Clcontent　of　0.01　and　0.05　wt%　for　the　existence　of　calcium　nitrate.　Calcium　ions　(Ca2+)　are　introduced　to　solar　salt　with　the　same　Clcontent　of　0.03　wt%　to　confirm　its　corrosion　effect　on　stainless　steel.　The　results　show　that　the　addition　of　a　small　amount　of　Cl　and　Ca2+can　reduce　the　corrosion　rate　of　solar　salt　on　316L　stainless　steel.　The　corrosion　products　morphology　analysis　by　SEM,　EDS,　and　XRD　test　show　that　the　calcium　rich　oxide　layers　containing　CaFeO4　was　found　in　the　corrosion　layer　of　stainless　steel,　which　inhibits　the　further　corrosion　of　stainless　steel　in　molten　salt.　This　finding　has　the　far-reaching　implications　for　inhibiting　corrosion　of　molten　salt　with　Cl　on　stainless　steel