The invention relates to a cooling method of an oil-immersed transformer and a structure, and belongs to the technical field of transformers. According to the technical scheme, one end of a tank output pipeline (2) communicates with the upper part of a transformer tank (1) and the other end of the tank output pipeline (2) is rotationally connected with a radiator (4) through a rotatable connecting device I (3); one end of a tank input pipeline (6) communicates with the lower part of the transformer tank (1) and the other end of the tank input pipeline (6) is rotationally connected with the radiator (4) through a rotatable connecting device II (5); the rotatable connecting device I (3) comprises a base plate (7), a spherical hinge ball (8), a turn plate (9) and a connecting pipe (10); the base plate (7) is rotationally connected with the turn plate (9) through the spherical hinge ball (8); and one end of the connecting pipe (10) is connected with the radiator (4) and the other end of the connecting pipe (10) is fixed on the turn plate. The cooling method and the structure have the beneficial effect that the cooling effect and the heat dissipation effect of the transformer can be improved.