<p>In order to master the evolution law of insulator string under degradation situation, a simulation method for the evolution of an insulator string under degradation situation considering the electric field distribution of lightning protection insulators is proposed. Combined with the quasi-static electric field, the electric field distribution of lightning protection insulators is solved in differential form, and the evolution equation of insulator string deterioration situation is obtained according to the damage evolution law, and the evolution result of insulator string deterioration situation is calculated. The evolution process of deterioration situation is simulated by finite element simulation software. The test results show that when the thickness of air medium is 5&#xa0;m, this method can effectively simulate the electric field distribution in dry and wet conditions. When the degradation degree is lower than 0.3, the insulators still have a certain bearing capacity; when the degradation degree is higher than 0.3, the degraded bearing capacity of insulators almost disappears, and the higher the electric field intensity, the faster the evolution of the degradation situation. When the strain exceeds 0.25, the higher the electric field intensity, the more obvious the evolution of the degradation situation of insulator string. It can simulate the evolution of insulator string deterioration.</p>