DC fault arc, especially series fault arc, is an important cause of fire in photovoltaic (PV) system. If not detected and interrupted in time, such dangerous events may lead to catastrophic fires, which will pose a serious threat to human safety and property. The mechanism and fault characteristics of DC fault arc analyzed. The DC fault arc detection and location methods in photovoltaic power generation system in recent years are summarized. We summarize and discuss the technical details of the recently published papers. Finally, aiming at the DC system, the problems that need to be solved at present are pointed out from the perspective of practical application, and the application scenarios and research directions of DC fault arc detection and fault arc location in the future are prospected.