The utility model provides an iron core air duct wall for a 330MW vapour-cooled generator, which is characterized in that the iron core air duct wall consists of a first air duct wall and a second air duct wall which are in mutual split joint, wherein the first air duct wall comprises a first air duct plate; a vent steel bar with a notch is arranged at a tooth part of the first air duct plate; the second air duct wall comprises a second air duct plate; an air duct cushion block is arranged on a yoke part of the second air duct plate; and one side of the first air duct wall provided with the vent steel bar is mutually split with one side of the second air duct wall provided with the air duct cushion block. The utility model has the advantages that the characteristics of cooling liquid can be fully utilized; the cooling liquid can flow in a radial direction, and can also flow in a circumferential direction; the cooling effect of the iron core of the 330MW vapour-cooled generator is improved; and the efficiency of the generator is improved.