The transmission tower-line systems play a vital role in power transmission. However, since most of the transmission tower-line systems are situated in rural areas subjected to various extreme weather conditions, transmission conductors are prone to be broken. In order to investigate the dynamic impact of conductor breakage on the transmission tower, a finite element model is established in ABAQUS, and the global state of the transmission tower is determined according to the base reaction. By calculating the impact coefficient of the main members in different parts of the tower under different working conditions, the changes of axial forces of the main members in different positions are shown, and the most severely impacted parts of the tower are identified. Finally, the simulation results are compared with the current norm, and the shortcomings of the criteria are pointed out. The results show that the main failure modes of transmission tower caused by wire breakage are bending failure and torsion failure, and the bending failure is more serious. When a single wire is broken, the impact caused by the rupture of the upper wire is the most serious, and the place suffering the greatest impact is the section between the crossarm connected with the broken wire and the adjacent crossarm. With the increase of the number of broken wires, the proportion of torsion failure increases, and the sections between two adjacent crossarms are damaged seriously. In addition, it is necessary to use dynamic methods to analyze structures, because using current codes and static methods to calculate the influence of wire rupture on structures cannot ensure that structures are still safe under the dynamic impact of wire rupture.