Abstract: Content of abstractIn order to study the influence of size factors on the electric field distribution of insulators, this paper establishes a calculation model for the electric field of pillar insulators in COMSOL multi physics field simulation software. Using parameters such as umbrella extension and umbrella spacing as variables, the parameterized scanning method is used to analyze and calculate the electric field distribution of pillar insulators. The results show that the average field strength on the surface of the pillar insulator is inversely proportional to the umbrella extension and umbrella spacing, while the maximum field strength is inversely proportional to the umbrella spacing and directly proportional to the umbrella extension. Moreover, as the equivalent diameter of the umbrella skirt increases, the maximum field strength at the end of the insulator increases. Increasing the creepage distance alone may reduce the insulator's ability to withstand pollution flashover. The accident case shows that due to the fact that the ground knife insulator that experienced flashover had three fewer umbrella skirts than the conventional insulator, and the designers adopted the method of increasing the diameter of the umbrella skirt to meet the requirements of the creepage distance, this resulted in a 26.19% increase in the potential difference between the first and last umbrella skirts of the ground knife insulator compared to the conventional insulator, and the overall field strength was also higher than that of the conventional insulator. Its ability to withstand pollution flashover was lower than that of the conventional insulator, The case analysis results have verified the correctness of the aforementioned conclusions.