Since transmission lines are liable to faults, its fault location technology with higher accurate is important to the operation of power systems. As a method with high accuracy, travelling wave based fault location is independent of fault resistance, symmetry of configuration, terrain of corridor, error of TA and TV, and can be used in DC transmission lines and series compensating lines. Recently, the advancements are made on the exploration of new theories, the signal pick-up and analysis, and the high-speed sampling and the mass storage facility are used in the development of travelling wave fault location devices.