The utility model relates to the technical field of power electronics. A double water-cooled transformer comprises an iron core and coils arranged on the iron core in a winding manner; a water pipe used for cooling the iron core is arranged inside the iron core; each coil is provided with a water cooling module, and the water cooling modules positioned between every two adjacent coils are sequentially connected to form a coil cooling circulating waterway. The double water-cooled transformer provided by the utility model is provided with the coil cooling circulating waterway used for temperature reduction of the coils, and is provided with a water pipe used for cooling the iron core, so that temperature reduction to the coils and the iron core can performed respectively, and the temperature control effect is obvious. The water inlet of the water pipe used for cooling the iron core is communicated with the water outlet of a water collector. Water flow enables the temperature of the iron core to be lowered.