This article preliminarily studies the influence of harsh environments on the flashover characteristics of ice-covered cantilever insulators in the catenary system. Ice accretion alters the electrical performance of cantilever insulators, and in heavily polluted areas, it may even cause insulator flashovers, seriously compromising equipment safety and the normal operation of railways. And ice accretion tests were conducted in an artificial climate chamber under various pollution types and gradients, and flashover characteristics were measured using transformer voltage application. The results show that there are differences in the flashover behavior and flashover paths of ice-covered insulators when two different coating methods, solid layer method and ice-covered water conductivity method, are used. The flashover voltage of cantilever insulators decreases following a negative power-law relationship as ice accretion time and pollution concentration increase.