The invention discloses a method for preparing a metal diffusion couple by a centrifugal method. In the method, a diffusion couple (represented as an A/B couple) composed of a metal (represented as A)and a metal (represented as B) is mainly prepared, and the A/B couple composed of solid-solid metals or solid-liquid metals can be prepared as needed. A pair of A and B wires or rods with the same length and the same diameter is placed into a quartz tube, a high vacuum is formed, and the tube is sealed by using oxyhydrogen flame. A middle position in the length direction of the quartz tube is vertically fixed on a long metal molybdenum rod, the molybdenum rod is connected with a motor, the quartz tube is placed in a resistance furnace, the quartz tube is rotated at a high speed in the furnace, so that the metal rod A and the metal rod B are in close contact with each other under the action of a centrifugal force to form an A/B diffusion couple, after the motor reaches a set rotating speed, after being kept for a certain period of time, the rotating speed is gradually reduced until stop, then the quartz tube is taken out for air cooling or quenching cooling, and finally the quartz tubeis broken to take out the prepared diffusion couple.