Abstract: The problem of abnormal heating of disconnect switch contacts is prominent and affects the safe and stable operation of the power grid. In order to detect abnormal heating in time, a preparation method for reversible color-changing coating is proposed and its performance is analyzed and studied. The reversible color-changing material is prepared by using a three-component method in which crystalline violet lactone is used as the chromogenic agent, bisphenol A as the chromogenic agent, and palmitic acid as the solvent. The optimal composition mass ratio of its components is also determined. The results show that, with the increase of the proportion of BPA, the color of material becomes deep, and the color-changing start temperature and end temperature both increase. With the increase of the proportion of palmitic acid, the color of the material becomes light, and its color-changing start temperature changes inconspicuously, while the end temperature decreases gradually. The color-changing microcapsule is prepared by in-situ polymerization method and subjected to differential scanning calorimetric analysis. Its temperature range of phase change is consistent with the temperature range of color change, and its thermal stability is good. The color-changing coatings with different mass ratios (permanent-room-temperature-vulcanized anti-contamination flashover composite coating : microcapsule) are prepared by the mixing and stirring method, and they have good color-changing performance. The water contact angles of the color-changing coatings with different mass ratios are all greater than 100°, and the flashover voltage values per unit length along the surface are all greater than 8.5 kV, exhibiting good hydrophobic and electrical resistance properties. The research results can provide a reference for online detection of thermally induced defects in disconnect switches in high temperature and high humidity operating environments.