The feasibility of integrating traveling wave fault location function into transmission line protection device is discussed, the design, key technologies and solution scheme of the integrated device with both transmission line protection function and traveling wave fault location function are proposed, prototype of the integrated device is developed. The device integrates traveling wave fault location function module based on transmission line protection device, uses DSP component to collect input signals from current transformer of the line protection device, takes bulk cache technology to improve the coverage rate of traveling wave fault location record, diagnoses traveling wave triggers by protection triggers to ensure the reliability of the traveling wave trigger, communicates through longitudinal protection channel by transparent frame transmission technique, and verifies the reliability and precision of traveling wave fault location with impedance fault location of the line protection device. The device also adopts traveling wave speed correction technology to minimize the error between traveling wave fault location results and actual results. The performance of the integrated device prototype developed by this paper meets the design requirement and engineering application requirement, and provides a developing trend of integration of line protection and traveling wave fault location in high or ultra-high voltage lines.