In the method of fault location using empirical wave velocity, because of the dispersion characteristics of travelling wave, the wave velocity changes with the change of frequency, and the fault distance is obtained by calculation has a large error. To solve this problem, it is necessary to accurately extract the time-frequency characteristics of travelling wave. This paper proposes a fault location method of DC line based on multisynchrosqueezing transform (MSST). Due to the multiple extrusion characteristics of MSST, the fault location method can effectively improve the time-frequency aggregation of signals, and identify the time-frequency characteristics and wave heads of traveling waves more accurately. By using this method, the time and frequency information of the traveling wave arriving at the measuring point are obtained, and the corresponding wave velocity is further obtained, and the fault distance is calculated based on the wave velocity, which reduces the error caused by the inaccurate identification of the wave velocity and the arrival time of the wave head. Finally, the effectiveness of the proposed method is verified by simulation and actual engineering data.