DC microgrid is an important pattern of energy collection and distribution for distributed power, and it is one of the key part of intelligent distribution in the future. At present, the protection technology of DC microgrid is still facing challenges, protection methods and equipment still lags behind the AC system, and the fast and accurate fault isolation requirements can not be met. This paper took the ring DC microgrid as a research object, analyzed the current fault component direction characteristics，and explain the directional pilot protection principle. In order to meet the characteristics of DC microgrid fault and the requirements of rapid protection, the protection scheme is designed based on the intelligent electronic device. The scheme has a clear protection zone and can quickly identify and isolate the fault immune to the impact of the fault type and location. Meanwhile the scheme has satisfactory performance to transition resistance. The DC microgrid models are established in PSCAD/EMTDC. The simulation results verify the effectiveness of the proposed scheme.