This paper mainly studies the electric field distribution on the surrounding of insulator when there is ice on sheds surface. Using finite element analysis software Ansoft Maxwell to construct the finite element model of line insulators. By doing simulation analysis on model of line insulators, we get electric field distribution on the surrounding of insulator when there is no ice distribution. Then through simulation analysis, we get the influence of the number, length and diameter of ice on the surrounding electric field of insulator. In the end, in order to improve reliability of power system. we make reasonable optimization suggestions by summing up the above analysis.