The invention relates to a wide area fast voltage controller of a wind turbine generator and a control method. The controller comprises a voltage deviation calculation section, a first dead zone section, a first amplitude limiting section, a first PI section, a reactive power deviation calculation section, a second dead zone section, a second amplitude limiting section, a second PI section, a first selection switch and a leading lag section. The voltage deviation calculation section, the first dead zone section, the first amplitude limiting section and the first PI section are sequentially connected. The reactive power deviation calculation section, the second dead zone section, the second amplitude limiting section and the second PI section are sequentially connected. The first input terminal of the first selection switch is connected with the first PI link. The second input terminal of the first selection switch is connected with the second PI link. The output terminal of the first selection switch is connected with the leading lag section. The technical scheme provided by the invention can improve the reactive power output of a wind turbine generator and rapidly suppress voltagesudden rises and sags.