The Al-5Cu alloys were prepared by different treatment methods, including adding a refiner Al-5Ti-1B, exerting a rotating magnetic field (RMF), and compound treatment of both refiner and RMF. The effects of treatment methods on the microstructure, properties, and solid solubility of the Al-5Cu alloy were investigated. The optimal magnetic field parameters and addition amount of refiner were confirmed by experiment. Results show that either RMF or adding refiner Al-5Ti-1B alone can refine the grain size, and the refining effect can be further improved by a compound refining treatment with optimized magnetic field parameters (120 A current and 8 Hz frequency) and 1.0wt.% Al-5Ti-1B refiner (RMF*+Al-5Ti-1B*). The average grain size is decreased to 68.1 µm, which is 60.8%, 21.1%, and 83.5% lower than that of the alloy treated by the optimized rotating magnetic field, the Al-5Ti-1B refiner, and the alloy without any treatment, respectively. The tensile strength and elongation of the alloy reach 232.5 MPa and 18.6%, respectively, which are obviously higher than those of the alloys treated by rotating magnetic field, Al-5Ti-1B refiner, and the alloy without any treatment, respectively. Additionally, the solid solubility of the alloy is also obviously improved compared to the alloys treated by other methods.