The necessity of studying on flashover mechanism of overhead transmission lines under forest fires is introduced. Fire disaster influence factors are introduced, the present research situation of flashover mechanism of Overhead Transmission Lines under Forest Fires, including the analysis of the existing test methods, then, the present methods to monitor forest fires Sapplied in transmission lines and its existing problems are summarized, and Putting forward new ideas that Laser radar technology applies in transmission lines to monitor forest fires, at the same time pointing out , combining Satellite remote sensing technology with traditional sensor terminal monitoring methods can improve the reliability and real-time of transmission line monitoring.