With the increased penetration of renewable generation such as photovoltaics and wind turbines, the equivalent inertia and equivalent damping of the power system gradually decrease, which will result in stability problems becoming more and more serious. Virtual synchronous generator (VSG) technologies can enable power electronic interface inverters to simulate the external characteristics of synchronous generators (SG), thereby controlling grid-connected inverters as synchronous inverters and greatly improving the grid's ability to accept distributed power supplies. Additionally, it also effectively reduces the impact of the traditional grid-connected inverter on the stable operation of the power system during the grid-connected and off-grid process, which shows natural friendliness to the power grid. Therefore, VSG technologies have great research value and wide application prospects. This paper first expounds the basic idea of VSG, then further analyses and studies it from mathematical modelling, control strategies, stability analysis and application prospects, and finally puts forward several possible future research directions based on the project of my task group.