Provided are an organic rare-earth solid micelle, a preparation method therefor, and a method for increasing the photoelectric conversion efficiency of a solar battery. A small organic conjugated ligand is taken as a first ligand, an amphiphilic diblock polymer is taken as a second ligand, and the first ligand and the second ligand are mixed and doped with a rare-earth chloride solution, and self-assembled to form an organic rare-earth solid micelle, whereby the fluorescence emission intensity and the fluorescence efficiency of the rare-earth element are improved. Next, the prepared organic rare-earth solid micelle is spin coated on an ITO layer of a solar battery, to prepare a solar battery with the organic rare-earth solid micelle. Therefore the sunlight absorption of a cell is increased, and the photoelectric conversion efficiency is improved. The preparation process is simple, low in cost, high in photoelectric conversion efficiency, and environmentally friendly.