Nowadays, the expansion of renewable energies (the wind, solar, ocean wave, fuelcell-some of them are natively DC) in power system as a potential solution for the environmental protection and lack of energy when the traditional energies are going to be exhausted. Besides, the development of fullness DC as storage technologies (batteries and ultra-capacitors), and DC loads (Data centers, electronic based office, home appliances, plug-in electric vehicles, variable speed drives and DC electric arc furnaces) are significantly increased. Furthermore, DC distribution leads to advantages than AC distribution such as reduced losses, safety, abatement of electromagnetic fields, and power quality improvement was shown in [2]. Moreover, in recent years, there are a lot of DG connected directly with DC grid and continuously connected to AC to created hybrid grid to increased the power efficiency. However, there are many problems in DC grid with DG and one of the most important is islanding detection, the same with AC grid. There are many papers about IDM for AC grid but until now, the investigation about IDM for DC grid is missing. Therefore, this paper will concern about the existing IDM papers such as [3]-[6], discussion about advantages and disadvantages of IDMs and proposed some potential solutions applied to DC grid. This paper will give us a view clearly, the trend, and difficulties in research about islanding detection methods in DC networks.