Abstract: Two typical nuclear power coating materials were selected, and the thermal conductivity of the materials was tested by ordinary heat flow meter method, heat protection heat flow meter method and flash method respectively. The results show that there was a big error between the flash method and the heat flow meter method in the test of inorganic zinc coating, which could not replace the method of ASTM E1530 standard. The results measured by the two heat flow meter methods were close, but there were still 30%—50% deviations. In the test of epoxy coating, the results obtained by the three methods were relatively close. In view of the fact that the current standards did not specify the key variables, it was recommended to develop a national standard for nuclear power coatings to improve the accuracy and consistency of test results. The research results could provide an important reference for the standardization of coating material testing.