The invention relates to the technical field of power electronics, in particular to a transformer cooling system. A double-water-cooling integrated temperature-reducing system for a clean energy transformer comprises a transformer iron core water circulation cooling system and a transformer coil water cooling module, wherein the transformer iron core water circulation cooling system comprises a transformer iron core and a water cooling system; the transformer iron core comprises laminated magnetic steel sheets; the water cooling system comprises a water flow pipeline and a sheet-like iron core water circulation module; water flow passes through the water flow pipeline; the sheet-like iron core water circulation module comprises a metal base plate; the water flow pipeline formed by metal water pipes is welded on the metal base plate; the sheet-like iron core water circulation module is embedded into the transformer iron core and is sandwiched between the two layers of magnetic steel sheets. By virtue of the design, the double-water-cooling integrated temperature-reducing system for the clean energy transformer has more outstanding advantages to transformers for clean energy such as solar energy, water energy and wind energy.