Abstract: In this paper,the experimental study on the forced convection heat transfer between molten salt and heat transfer oil was carried out by using the binary mixed molten salt（KNO₃-Ca（NO₃）₂） prepared by our group.The total heat transfer coefficient of the molten salt-heat transfer oil under different working conditions was obtained.The convective heat transfer coefficient and the convection criterion number correlation of the molten salt in the tube and the molten salt side under the fully developed turbulent flow and transitional flow in the tube were obtained respectively by the Wilson’s Separation Method and the Least Squares Method.The results show that the maximum deviation of turbulent experimental data is +23% compared with the classical correlation.By considering the variable properties of high-temperature molten salt,the viscosity equation is used to correct the Dittus-Boelter equation correlation.It is found that the maximum deviation between the modified Dittus-Boelter equation and the experimental test results is-15%.The deviation value is significantly reduced.The maximum deviation of the transitional flow experimental data from the Hausen equation and the Gnielinski equation is 10%.The test shows that the experimental results of this work are in good agreement with the classical heat transfer formula mentioned above,which isdications that the heat transfer relationship is still applicable to high temperature molten salt.