Molten　salt　is　popular　as　heat　transfer　fluid　in　solar　energy　applications　in　the　temperature　level　of　hundreds　of　degrees　or　higher,　but　it　would　be　a　tedious　work　to　measure　the　thermal　conductivity　at　elevated　temperature　due　to　convective　and　radiative　effects.　In　this　paper,　a　theoretical　model　is　presented　for　predicting　the　thermal　conductivity　of　binary　molten　salts,　in　which　only　data　of　thermal　conductivity,　density　and　mass　fraction　of　each　component　salt　are　needed.　Comparisons　with　experimental　data　show　that　the　model　gives　prediction　of　thermal　conductivity　with　errors　less　than　6.4%.　The　linear　mixing　rule,　however,　always　gives　large　positive　errors,　especially　at　about　0.5-0.5　mol　fraction,　which　may　sometimes　reach　33.8%.　The　present　work　indicates　that　accurate　prediction　of　thermal　conductivity　of　molten　salt　mixture,　even　at　elevated　temperature,　can　be　achieved　if　the　thermal　conductivity　of　pure　compounds　potentially　applied　in　molten　salt　mixtures　is　measured　with　enough　accuracy.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.