Abstract The monitoring equipment on the transmission tower mostly uses solar energy and wind energy for power supply, which is unstable with low reliability. Based on optical fiber energy transmission technology, photoelectric energy conversion technology, and induced current energy extraction technology, a transmission line monitoring terminal that can take energy from the transmission line is developed in this paper. The energy transmission optical fiber and the composite insulator had to be put together and become a new composite insulator, which can transfer light energy from the high-voltage side to the tower through. It can supply power to the micrometeorology, tower tilt monitoring device, video monitoring, and other monitoring modules installed on the tower, and transfer the above monitoring information to the Internet cloud relying on the Internet of things technology. A new power supply scheme for transmission line online monitoring device is provided, which provides a new idea for the construction of a “smart transmission line”.