In order to solve the traditional long-distance ultra-high voltage (UHV) transmission-line risk warning system in the design process, it neglects the classification step of early warning information, which leads to the poor effect of risk early warning, the authors propose fault prediction and simulation analysis of UHV transmission-line based on thermal energy transformation. In the hardware design part, the network video server is used to design the host control module, and the video decoding chip is used to convert the acquired analog signal into digital signal, then it is transmitted to the serial port server, and the risk warning circuit is designed based on it. In the software design, GA-BP algorithm is used to obtain the number of nodes in the middle layer, the constraint range is determined, and the warning information is classified to realize the risk warning of long-distance UHV transmission-lines. The experimental results show that the warning accuracy of the system under different conditions is high, and the highest warning effect can reach 95%. It is proved that the classification recall rate of early warning information is high, which can effectively resist interference and provide strong support for the safe operation of transmission-lines.