In order to prevent the damage of insulator base during laser cleaning, the damage test of ceramic insulator under laser irradiation was carried out in this paper. A 1 064 nm pulsed laser was irradiated on the surface of a porcelain insulator to explore the damage rule of the porcelain insulator under different energy density, pulse number and irradiation time. A scanning test was carried out on the surface of the porcelain insulator, and the laser damage threshold of the porcelain insulator was determined by image method. The experimental results show that with the increase of laser energy density, pulse number, and irradiation time, the diameter of insulator surface pit gradually increases and finally tends to a constant value, which is about 1.3 times of the diameter of focused spot. When the scanning speed decreases, the damage morphology changes from speckle to stripe, and the roughness increases with the increase of energy density and the decrease of velocity. Based on the damage criterion of porcelain insulator with image method, the damage energy density threshold was obtained.