With the increasing scale of the power grid, real-time monitoring requirements for on-site data of power systems in various countries around the world are getting higher and higher. The high-voltage distribution network is widely distributed, spanning rivers, mountains, deep valleys, jungles, and other complex and variable environments so that it is susceptible to short-circuit faults caused by various natural disasters and other environmental factors. Aiming at the high proportion of single-phase grounding faults in the distribution network, the transient fault recording system is used to locate the fault. Fault indicators are consisted of three acquisition units installed on three-phase lines, an aggregation unit, and a master station. In this paper, a new type of transient fault recording system with high sampling rate and high precision clock synchronization is researched and developed. And introduced its hardware structure and function realization. Field experiments have proven that the developed fault recording system work reliably and can effectively collect three-phase transient currents in the distribution network.