As the carrier of high voltage electric power，transmission tower-line system is an important lifeline project，which safety and reliability may directly affect economic development. Once damaged due to natural disasters，it may result in unpredictable losses and negative social impacts. In recent years，extreme weather and geological disasters occurred frequently，and as a result，transmission tower-line systems were severely damaged，which received widespread social concerns. In this work，the disaster causes and failure modes of transmission lines were particularly discussed，and current measures or approaches for ensuring the safe operation of transmission tower-line system were summarized from three aspects，namely，structural design，numerical analysis and experimental verification. Based on the generalization and summation of these problems，it is aimed that the defects and deficiencies in design of transmission tower-line system can be ruled out，the ability of structures to resist the external environmental disasters can be improved，and the consciousness of designers on importance or reliability of power safe operation can be enhanced.