在寒冷地区建设±800 kV特高压直流输电线路，需要解决构件低温脆断的设计难题，防止钢结构构件在未达到屈服应力的情况下发生低温冷脆破坏。以±800 kV哈密—郑州直流输电线路为研究对象，结合国内外低温冷脆现象领域的理论和试验成果，介绍了低温环境下铁塔构件的力学性能及原理，结合工程实际提出了低温环境下构件的强度设计方法，并对设计参数进行了研究，推荐了合理的折减系数，所得结论可供直流输电塔结构构件设计参考。

For ± 800 kV UHV DC transmission line construction in cold regions, it is necessary to solve the design problem of low temperature brittle fracture, in order to prevent the brittle fracture of steel structure members under low temperature without reaching the yield stress. Taking ±800 kV Hami-Zhengzhou DC transmission line as the study object, this paper introduced the mechanical properties and principles of tower components under low-temperature environment, based on the theory and test results of brittle fracture under low temperature at home and abroad. Combined with practical engineering, a strength design method was proposed and the design parameters were studied in detail for steel structure members under low-temperature environment. At last, some reasonable reduction factors were recommended. The results presented in this paper could be used as references for the design of DC transmission tower.