Transmission tower-line systems with different elevations in mountainous areas are established in this paper. The change curve of ice increasing with time was given according to the data of ice record. Considering the influences of height difference, ice increasing, plastic analysis of transmission tower is carried out. It can be concluded that the ultimate bearing capacities of ice coating of the tower is significantly influenced by the elevation of the towers beside it. It also can be concluded that the ultimate bearing capacity of ice coating can be improved only when the section of weakness member is increased.