A method for forming a precursor solution for metal organic deposition includes dissolving an additive-free first precursor composed of a rare earth element, a second precursor comprising barium, and a third precursor composed of copper into an acid to form a compound solution; dissolving the compound solution into a solvent to form a pre-precursor solution; and evaporating the solvent from the pre-precursor solution to form a precursor solution having an increased viscosity; wherein at least one of the first precursor, the second precursor, and the third precursor is dissolved into a fluorine-free acid. A method for forming a superconducting thick film from the above precursor solution includes forming a thick film by a one-time coating of the precursor solution having an increased viscosity onto a biaxially-textured base followed by heat treating to form the superconducting thick film having a thickness of about 0.2 μm or more and having no cracking.