The security protection strategy for differential protection of 5G-based distribution network is discussed. Firstly,the architecture and implementation principle of differential protection of distribution network are given. Secondly,the security of 5G and 4G networks is compared and analyzed. Combined with the security challenges of 5G,the security protection requirements for 5G-based distribution network are analyzed,and then two security protection goals for differential protection of 5G-based distribution network with SA and NSA are proposed. Finally,the security risk points and countermeasures are given based on the data flow and boundary conditions of the differential protection. The results demonstrate that the proposed security protection strategy is effective.