Transmission towers and steel poles are both supports used for power transmission, collectively referred to as transmission lines. Due to their ease of construction and small footprint, steel poles are mostly used in urban or suburban areas. Transmission towers, on the other hand, are mostly used for longer lines and are primarily installed in areas outside urban or suburban districts.

A transmission line tower is a tower-like structure used for power transmission. Its structural characteristic is that various tower types are all spatial truss structures. The members are mainly composed of single equal-leg angle steel or built-up angle steel sections. The materials commonly used are Q235 (A3F) and Q345 (16Mn). The connection between members is achieved using rough bolts, relying on the bolt's shear resistance. The entire tower consists of angle steel, connecting plates, and bolts. Individual components, such as tower leg assemblies, are welded together from several steel plates. Therefore, hot-dip galvanizing for corrosion protection, transportation, and construction erection are extremely convenient. For towers with a height below 60 meters, step bolts are installed on one of the main vertical members to facilitate construction workers' climbing access.

The voltage classes for transmission line towers are: 35KV, 110KV, 220KV, 330KV, and 500KV.