The invention discloses an automatic quick cooling device of a power transformer. The automatic quick cooling device comprises a spraying device and a control device, wherein the spraying device is arranged on the two sides of the transformer and comprises a pump, a quick cooling agent pipeline and a plurality of large-umbrella-diameter sprayers, the outlet of the pump is separately connected withthe inlets of the large-umbrella-diameter sprayers through the quick cooling agent pipeline; the control device comprises a metal cabinet, a first cooling branch pipe, a second cooling branch pipe and a control circuit, wherein the first cooling branch pipe and the second cooling branch pipe are identical in structure and are arranged in the metal cabinet. In the automatic quick cooling device, the cooling agent with dry ice and softened water as main components is adopted, and cooling is automatically conducted through background data sharing with a temperature monitoring system of the transformer when it is monitored that the temperature exceeds the limiting value; through booster pump, the cooling agent passes through the large-umbrella-diameter sprayers around a transformer body to synchronously and quickly spray and cover up the transformer body, the quick cooling agent is quickly vaporized when heated so as to absorb the heat on the surface of the transformer body, and the quickcooling aim of the transformer body is achieved.