The present invention relates to a method of preparing an oxide superconducting film, the method includes reacting a metal acetate containing metal M selected from the group consisting of lanthanum, neodymium and samarium with fluorocarboxylic acid having not less than three carbon atoms, reacting barium acetate with fluorocarboxylic acid having two carbon atoms, reacting copper acetate with fluorocarboxylic acid having not less than two carbon atoms, respectively, followed by refining reaction products, dissolving the reaction products in methanol such that a molar ratio of the metal M, barium and copper is 1:2:3 to prepare a coating solution, and coating a substrate with the coating solution to form a gel film, followed by calcining and firing the gel film to prepare an oxide superconducting film.