The utility model discloses a safety pre-warning device for a high-voltage transmission line. The safety pre-warning device comprises a fixed unit, a moving unit and an alarm display unit, the fixed unit comprises a first microcontroller, and a base station differential GPS, a power supply module, a camera module, a remote communication module and a first communication module which are connected with the first microcontroller; the remote communication module is in communication connection with a remote main station; the mobile unit comprises a second microcontroller, a mobile station differential GPS, an electric field detection module and a second communication module, wherein the mobile station differential GPS, the electric field detection module and the second communication module areconnected with the second microcontroller. The second communication module is in communication connection with the first communication module. The alarm display unit comprises a third microcontroller,and an audio playing module, a display module, a storage module and a third communication module which are connected with the third microcontroller; the third communication module is in communicationconnection with the first communication module and the second communication module; according to the utility model, high-efficiency real-time monitoring of a high-voltage power transmission line is realized, personnel and material investment is reduced, and power supply reliability is guaranteed.