Abstract: Transmission tower line system is a long-span spatial structure, which bears different ground motions. It is affected by traveling wave effect, partial coherence effect and local site effect. For the long-span spatial structure of transmission tower line system, multi-dimensional and multi-point earthquake excitation is one of the main reasons for its earthquake damage. It is of great practical significance to study its response law under multi-dimensional and multi-point earthquake action. In this paper, the large mass method is used to simulate the multi-dimensional and multi-point seismic action of the transmission tower line system, and the calculation results are compared with the time history analysis results of the single tower structure.