The outbreak frequency of the galloping caused by wind deflection of transmission lines is relatively high, which seriously affects the normal and stable operation of the power system and brings significant losses to the national economy. Therefore, the real-time online monitoring of the galloping of transmission lines has always been a research hotspot in this field. Starting from the causes of the galloping of transmission lines, this paper discusses the online monitoring technology and system performance of the galloping of transmission lines, analyzes the commonly used online monitoring methods for galloping, related research and existing problems, and summarizes the difficulties of the current online monitoring technology for the galloping of transmission lines. A fusion monitoring method of "MEMS vibration sensor + BD differential positioning" is proposed. With the communication networking mode of the integration of WSN/GPRS/BD three networks, a real-time online monitoring network platform for the galloping caused by wind deflection of large crossing transmission lines with the integration of sky, ground and space based on Beidou communication is established to achieve the real-time monitoring of the galloping of transmission lines, which has practical guiding significance for carrying out the research on the real-time online monitoring of the galloping of transmission lines.