Abstract: How to clean the aged RTV coating is the problem in the operation of composite porcelain and glass insulator, and laser cleaning technology is expected to solve the current difficulties. In this paper, the key index energy balance technology of laser cleaning RTV coating is studied. When the temperature of RTV coating irradiated by facula is over 409.67 ℃, the coating can be cleaned. Maintaining the working distance between the coating and the lens can effectively improve the utilization rate of laser energy. When the spot spacing is less than 0.15 mm under the output of 75-W laser, the complete cleaning of the coating can be realized, whereas the glaze damage on the cleaning surface will occur. The variance of spot spacing can reflect the balance level of laser energy, which is inversely proportional to the length of one-dimensional line of laser cleaning and is directly proportional to the pulse frequency of the laser. When the power is 66~75 W and the variance of spot distance is 0.09, the RTV cleaning effect is the best. The back-and-forth cleaning mode can effectively solve the problem of poor energy distribution balance caused by uneven surface color. The energy required to achieve a fully cleaned unit area is 2.2~2.5 J/mm². Setting a back-and-forth cleaning mode is more uniform and effective compared to setting a single cleaning mode when laser cleans the RTV coating.