DC distribution network has been gained increasingly interests due to its flexible control, excellent power quality, and capability to integrate distributed generators and DC loads. However, the fault characteristics of DC networks are different in nature as compared with AC power networks. The protection technology of an AC network is hard to be directly applied into the DC distribution network. Besides, the over-current capability of DC converters is weak and the restoration control is relatively complicated, which presents higher requirements for fast and accurate fault identification, location and isolation. Therefore, the protection technology becomes one of key technologies for developing DC distribution network. In this paper, the topology of DC distribution network is discussed by analyzing the fault occurrence, identification, location and isolation. The fault identification and location are considered as the key issues in DC distribution network protection. On the basis of this, the main points and difficulties of the protection technology are analyzed. The state of the art of fault identification and location in DC distribution network is evaluated and the technology perspective is investigated as well.