The traveling wave fault location approach for overhead transmission lines is widely applied in actual power grids due to its better fault location accuracy compared with conventional power frequency data-based methods. However, the traveling wave fault location approach is highly related to the frequency distortion phenomenon of traveling wave propagation velocity, which includes two parts: the distortion caused by the reflection and refraction of the transformer substation and the attenuation caused by the distributed resistance of transmission lines. This study aims to improve fault location accuracy, by developing a complete theoretical analysis of the distortion of traveling wave signals and an improved traveling wave fault location approach that considers distortion. Using the PSCAD/EMTDC simulation tool, a typical 500 kV case study model is established to verify the fault location accuracy of the proposed traveling wave fault location approach under the effects of different fault type, fault location, and grounding resistance.