Transmission line traveling wave protection uses traveling waves generated by faults to quickly identify faults, has ultra-high-speed action performance, and is not affected by factors such as power system oscillations, transition resistance, distributed capacitance current, and current transformer saturation.It is an ideal ultra-high voltage line relay protection method.Firstly, the development process of traveling wave protection is reviewed, and the domestic and foreign research status from three aspects of traveling wave signal extraction, signal processing technology development and engineering practice are summarized.Secondly, the basic principles of traveling wave protection are introduced and the advantages and disadvantages of various traveling wave protection principles are analyzed.The progress of related theoretical research is summarized, and a horizontal comparison and applicable scenarios for various traveling wave protection principles is conducted.Next, the main needs to be solved for the practical application of traveling wave protection technology problems are discussed and corresponding solutions are put forword.Finally, the development trend of traveling wave protection is prospected, which provides a reference for the subsequent research of traveling wave protection technology.