Transmission lines are susceptible to damage by a variety of disasters such as high winds and ice cover, which seriously threaten our energy security. At present, the study of wind and ice disasters on transmission lines is mostly focused on low altitude areas, however, many west-east transmission lines cross the vast plateau area, in which the long cross-burden transmission towers occupy a larger proportion, in order to ensure the safe operation of transmission lines in high altitude areas, this paper establishes a long cross-burden transmission tower-line system refinement model relying on a ± 800 kV UHV DC transmission project, based on the ice-covering conditions of the high-altitude areas, respectively, the establishment of the transmission towers and transmission lines of the ice-covered working conditions. At the same time, the wind load characteristics of high and low altitude areas are compared and analysed, taking into account the influence of environmental factors such as air density, topography and geomorphology in high altitude areas. Finally, based on the ice-covering conditions and wind load characteristics in high-altitude areas, the wind vibration response analysis of the long crossbar transmission tower-line system was carried out. The results show that the wind profile at high altitude is relatively gentle, the displacement response at the cross-burden of the long cross-burden transmission tower-line system is larger than that at the top of the tower, and the maximum displacement response of the structure under ice and wind loads occurs at the midpoint of the cross-burden end.