Abstract: Extreme weather events occur frequently under global climate change intensification. Under the influence of energy transition policies and geopolitics, primary energy supply and load levels are highly uncertain. China is in the construction stage of a new power system with an increasing proportion of renewable energy; the problem of power and energy balance under extreme scenarios is highlighted and shows a tendency to intensify. Based on this, this paper summarizes the research on extreme scenarios in the New Power System from the perspectives of the basic connotation of extreme scenarios, simulation and generation technology, application in the power system, countermeasures, etc. Firstly, the definition and characteristics of extreme scenarios are summarized, and the connection between extreme scenarios, extreme events, worst scenarios, and other concepts is pointed out. In contrast, the method of constructing extreme scenarios is concluded. Subsequently, the direct and indirect generation methods of extreme scenarios are sorted out for the small sample characteristics of extreme scenarios; the application methods of extreme scenarios in the power system and specific application areas are discussed; finally, the countermeasures of extreme scenarios are proposed at four levels by combining the existing research and actual engineering cases, and the follow-up research direction for extreme scenarios is highlighted, providing ideas for the subsequent construction of a flexible, reliable and supply-demand balanced power system.