The invention discloses a method for preventing resonance of a stator end winding of a large turbo generator. The method is characterized in that a 'double-point' mechanism is provided, and the resonance of the end winding is prevented in advance according to the mechanism. The 'double-point' mechanism indicates that the resonance of the end winding of the large generator must simultaneously satisfy the following two conditions: (1) the magnetic pull frequency is equivalent to or approximate to the inherent frequency of the end winding; and (2) circumferential travelling wave number of a principal mode is equivalent to pole number of the generator. When the stator end winding of the generator is resonant, the inherent frequency of the end winding can be adjusted, symmetry of the structure of the end winding can be changed selectively as well, and the shape of the structural principal mode is changed, so that vibration of the end winding is reduced and eliminated. The method is capable of providing guidance for vibration design, accident analysis, model change and operation and maintenance of the end winding of the large turbo generator.