The utility model discloses a passive magnetorheological damping device for end winding of large-size power generator. The damping device comprises a plurality of passive magnetorheological dampers which are equipped on an external wall surface of the end winding of the power generator and have same structures. The plurality of passive magnetorheological dampers are uniformly arranged on the external wall surface of the end winding of a motor along a circumferential direction. The other end of each passive magnetorheological damper, which is far from the external wall of the end winding of the power generator, is fixedly connected with the base of the power generator through a bracket. The plurality of passive magnetorheological dampers are used for inhibiting vibration which is generated by the end winding of the power generator. The passive magnetorheological damping device can effectively inhibit end winding vibration of the large-size power generator through the end leakage magnetic field of the end winding of the power generator, and furthermore has self-adaptability.