The utility model discloses a time service unifying device of an electrical power system. The time service unifying device comprises a main clock unit and a spare clock unit and multi-path expanding clock units, wherein the main clock unit and the spare clock unit are in a mutual hot spare state; the main clock unit and the spare clock unit are used for receiving external time reference signals; time signal output ends of the main clock unit and the spare clock unit are respectively connected with main and spare clock delay compensation modules arranged in the expanding clock units; and the time signal output ends of the expanding clock units are respectively connected with the time signal input end of electrical power systems. The time service unifying device disclosed by the utility model can effectively eliminate random errors caused by satellite signals and cumulative errors caused by constant-temperature crystal oscillators, so that the synchronism of time service time of various systems and devices in the electrical power systems can be ensured, and the requirements of intelligent substations and large main scheduling states on the time service can be met.