The advantages and disadvantages of heat transfer performance of solar power generation technology affects the uti-lization of solar energy.Graphite was selected as the additive to enhance the heat transfer performance of the phase change material and the ternary mixed molten salt（K₂CO₃-NaCl-Li₂CO₃） according to the mass fraction of graphite of 5%,10%,and 15%.TC3000 universal thermal conductivity tester was used to measure the thermal conductivity of sixteen samples,and the cyclic stability of 300 cycles of energy storage and release experiment samples was tested.The experimental results showed that the thermal conductivity of the mixed phase change material after adding graphite can be increased to 3.38 times that of the original mixed material.When the graphite content was 15%,the thermal conductivity of the mixed phase change material was the largest.After 300 times of energy storage and energy release experiments,the thermal conductivity of the material remained basically stable,and the fluctuation was no more than 15%.As an additive of strengthening materials,effectively improve the heat transfer performance of strengthened materials,graphite has practical engineering application value.