Abstract: Ternary nitrate salt is a major kind of hightemperature heating medium in chemical production.Measurement results of thermal conductivity are not very accurate because of high melting point,strong corrosiveness and convective and radiative heat transfer.Therefore,thermal conductivity of ternary nitrate salt was calculated by using various formulas of the models,such as Kincaid-Eyring equation,Rao equation,Gustafsson equation,and rough hardsphere model.Compared to the previous measuring values,results showed that the calculated values from rough hardsphere theory is similar to measured values.Therefore,rough hardsphere theory is reasonable for calculation of thermal conductivity of molten salts.