As the transmission voltage level increases, the tower is also getting higher and higher, and its spatial structure changes from bottom to top greatly. The modeling of the Ultra-High Voltage(UHV)tower plays an important role in lightning protection analysis of transmission lines. If the UHV tower still adopts the multi-surge impedance model, the effects of changes in the spatial structure of its high altitude cannot be reflected. Therefore, the non-uniform transmission line model is developed based on the physical structure of the tower. To study the influence of the tower′s spatial structure changes on its electromagnetic transient characteristics, the nominal height is modeled by several surge impendences. Finally, the lightning electromagnetic transient responses of the tower with the non-uniform transmission line model and with the multi-segment multi-surge impedance model are compared and analyzed. It shows that compared with the multi-surge impendence model, the non-uniform transmission line model is more suitable for lightning transient analysis of UHV tower.