Abstract: Glaze icing has serious impacts on the safety of the transmission lines, and the icicles produced by glaze distorts the potential and electric field on the insulators. In order to study the impacts of the lateral icing on the potential and electric field distribution along composite insulators, the ANSYS software is used to establish a finite element model for the icing of the 500 kV composite insulators. According to the phenomenon that the icicles grow laterally on the insulator both in the field and laboratory, the impacts of various icing patterns on the potential and electric field distributions is analyzed with the simulation model under different conditions, including changing the length, angles and locations of the lateral icicles, and the lateral and vertical icing appearing in the same time. The simulation results show that under the glaze condition, the change of the length and locations of the lateral icicles has little impact on the potential and electric field distribution along the icing composite insulator.With the decrease of the vertical angle of lateral icicles, the potential and electric field distributions on the surface of composite insulators distorts increasingly. It is concluded that the vertical icicles have a major impacts on the potential and electric field distribution along the composite insulator.