The invention belongs to the technical field of preparation of rare earth europium organic coordination compound and macromolecular polystyrene composite fibers by electrostatic spinning and relates to a method for preparing rare earth fluorescence micro / nano fibers, which comprises: placing europium oxide in an excessive amount of diluted hydrochloric acid to react the europium oxide with the excessive amount of diluted hydrochloric acid completely, allowing the excessive hydrochloric acid to volatilize to obtain europium chloride, reacting the europium chloride, acetylsalicylic acid and phenanthroline, which are in a mass ratio of 1:2.1:0.78, in ethanol in the presence of triethylamine serving as a complexing agent and catalyst, adjusting the pH value to make the chloride, acetylsalicylic acid and phenanthroline react completely, washing, filtering under vacuum and drying to obtain white powdery rare earth coordination compound; and dissolving the rare earth europium coordination compound and a macromolecular material in solution of tetrahydrofuran or trichloromethane respectively, mixing, and uniformly stirring to obtain solution of precursor, and performing electrostatic spinning to obtain micro / nano fibers having smooth appearance and strip structures. In the invention, the preparation process is simple, and the product has low cost, good fluorescence effect and high performance and can be widely used in fields of electrical, optical and chemical materials and the like.