The utility model relates to the technical field of power electronics, in particular to a high-frequency single-phase water-cooled transformer. The high-frequency single-phase water-cooled transformer comprises a shell, wherein an iron core is arranged in the shell, a primary winding and a secondary winding are wound on the iron core, the primary winding and the secondary winding are made of oxygen-free copper pipes through winding, the primary winding and the secondary winding are arranged in a staggered way, and insulating bands are wrapped between turns of the primary winding and the secondary winding; the shell is provided with a first water inlet, a first water outlet, a second water inlet, a second water outlet, a third water inlet and a third water outlet; one end of an oxygen-free copper pipe which forms the primary winding is connected with the first water inlet and the other end is connected with the first water outlet; an oxygen-free copper pipe which forms the secondary winding is provided with at least two independent cooling water flow passage, one end of one water flow passage is connected with the second water inlet and the other end is connected with the second water outlet; one end of another water flow passage is connected with the third water inlet and the other end is connected with the third water outlet. Since independent circulating water paths are arranged, the high-frequency electrical working performance of the transformer is ensured not to be changed.