The invention provides a large-size single crystal copper foil preparation method, wherein a polycrystalline copper foil is used as a raw material, one end is cut into a tip, and the large-size singlecrystal copper foil is prepared by using a special annealing process. According to the present invention, with the method, the problem of the high price of the single crystal copper foil is solved; and the preparation of the large-size single crystal copper foil is achieved through the simple method.