Underwater robots are the key equipment for subsea infrastructure inspection and marine environment survey. Subsea wireless charging stations can power underwater robots in-situ effectively. The principle of the magnetic-coupling underwater wireless power transfer technology is introduced. The structure of the electromagnetic couplers, the topology of the compensation networks and the analysis of the eddy current losses are the key issues of wireless charging stations for underwater robots. The technology status and application progress of subsea wireless charging stations are summarized. The development trends of basic theories and applications of subsea wireless power transfer technology are prospected.