The DC microgrid has become a typical distribution network due to its excellent performance. However, a well-designed protection scheme still remains a challenge for DC microgrids. At present, researches on DC microgrids primarily focus on the topology structure, control method and energy control, while researches on fault analysis, detection and isolation have not drawn enough attention. Therefore, this paper intends to depict the current research status in different relative areas and review the proposed protection strategies in order to help researchers to have a clear understanding on DC microgrid protection. Meanwhile, to solve the protection issues and promote the development of the DC microgrid, this paper points out the key areas of future research. The future protection research directions lie in the development of novel protection devices, which are based on electronic technology to provide loose protection constraints and the improvement of suitable protection schemes. In addition, the novel concept of coordinated strategy of control and protection of the DC microgrids is explained.