With the development of high voltage and large capacity power electronic technology, more and more power electronic devices have been put into operation. Hence, the future power system must be the power system with presence of massive power electronic devices, which is defined as power electronics based power system. However, with the large scale integration of the power electronic devices, the inertia and damping ratio of the power system is decreasing, adversely impact the safe and stable operation of the power system. The virtual generator technology can make the power electronic device emulate the inertia and damping feature of the conventional rotating machine, and help to address the safe and stable issues faced by the power electronics based power system. The basic principles of the virtual synchronous generator and virtual DC generator are described in this paper. Moreover, the application prospective of virtual generator technology in PV generator and wind plant, power electronic transformer, flexible AC and DC transmission, as well as load response and control is introduced. Finally, the development trends of the virtual generator technology are discussed.