The invention discloses a method for preparing a REBCO superconducting thin film. The method comprises the following steps: 1, preparing a precursor solution; 2, dip-coating the precursor solution on a base by adopting a dip-coating method after heating, so as to obtain a wet film coated on the surface of the base; 3, carrying out heat treatment on the wet film coated on the surface of the base, so as to obtain the REBCO superconducting thin film. The precursor is prepared by reaction of REBCO superconducting powder and propionic acid, and the reaction rate of the REBCO superconducting powder and propionic acid can be facilitated by adding a little of trifluoroacetic acid. By adopting the precursor, a thin film with a pure superconducting phase is obtained, and the fluorine content can be obviously reduced. Meanwhile, the content of introduced effective fluorine can be accurately controlled by adding polyvinylidene fluoride, so as to play a role of inhibiting barium carbonate. Meanwhile, by adjusting the viscosity of the solution, dip-coating and film formation are facilitated, and preparation of a strip is achieved. By adopting the method disclosed by the invention, the structure of the superconducting film can be obviously improved, and the current-carrying performance of the superconducting film at 77K can be improved.