The invention discloses a method for preparing a boron-doped YBCO (Yttrium Barium Copper Oxide) superconducting film by a one-step heat treatment process, which belongs to the technical field of materials. With yttrium acetate, barium trifluoroacetate and copper isocaprylate as materials, ethanol as a medium and boric acid as a dopant, the boron-doped YBCO superconducting film is prepared by thermal crystallization. According to the method disclosed by the invention, a boron element is uniformly doped into the YBCO film, the viscosity of precursor solution is increased, the shrinkage of the film in the process of YBCO heat treatment is relieved, consequently, the preparation of the boron-doped YBCO superconducting film by the one-step heat treatment process becomes possible, and the quality of film formation is ensured. In addition, the boric acid is generated into diboron trioxide under the condition of high temperature, which is doped in the produced film to serve as a pinning center in the form of a second phase, and thereby the electric property of the film in a magnetic field is improved. The efficiency of production is high, and the method has a great application prospect.