One of the key technologies for realizing the current differential protection principle based on 5G communication in distribution networks is current data synchronization at both ends of a section. This paper analyzes the adaptability of the existing data synchronization methods to 5G current differential protection and introduces time synchronization indexes and implementation architecture in the 5G protocol. This paper proposes a practical route of data synchronization using high-precision time information in 5G communication. A timing scheme for a base station based on 5G signal parameters is designed. Two types of timing signals suitable for current differential protection of a distribution network are introduced. We propose a current differential protection data synchronization method based on the B-code and analyze its error. Theoretically, the proposed scheme can realize the time synchronization deviation at both ends of the line is no more than 20.8 microseconds, and the phase angle deviation at both sides is less than 0.5 degrees, which fully meets the requirements of current differential protection. This work is supported by the National Natural Science Foundation of China (No. 51877127) and the Science and Technology Project of Shandong Electric Power Company (No. 5206011900DG).