Abstract:High-voltage transmission line is very important to the entire power system, but it is vulnerable to faults.It is important to repair transmission line and to ensure the safety, reliability in locating the faults quickly and accurately.This paper describes the research contents and the status quo of the use of wavelet transform for analyzing power system both in China and abroad.Wavelet transform provides a useful maths taol for analyzing and processing signals.Traveling wave theory is utilized in capturing the travel time of the transients along the monitored lines between the fault point and the relay.