With the rapid development of the electronics industry, increasingly stringent requirements have been placed on battery endurance and power transfer efficiency (PTE). To meet the demands of modern high-technology society, numerous research teams have invested substantial efforts in wireless charging technologies. At present, wireless charging mainly includes electromagnetic induction-based wireless charging, magnetic resonant coupling-based wireless charging, and microwave-based wireless charging. By comparatively analyzing the operating principles of these three approaches, this paper summarizes their respective advantages and disadvantages. Electromagnetic induction-based wireless charging is highly constrained by transmission distance and is therefore suitable only for short-range power transfer. Magnetic resonant coupling-based wireless charging enables relatively longer transmission distances; however, it poses potential safety risks, as resonance may occur between the charging equipment and conductive objects in the surrounding environment under certain conditions. Microwave-based wireless charging is well-suited for radio-frequency wireless power transfer (WPT) in the microwave band. Through frequency-band adjustments, it can be extended to long-distance wireless power transfer across multiple bands. In the future, improvements in coil stability, transmitter frequency tuning, and bandwidth expansion may further enhance the power transfer efficiency and application potential of wireless charging technologies.