The utility model discloses an automatic trickle heat sink of main transformer radiator, set up the water pipe in main transformer radiator upper end including one, water pipe one end is connected with water supply line, and the other end is water pipe plug, establish an ordinary valve, a solenoid valve on the water pipe, set up a plurality of trickle shower nozzles on the water pipe route, a control circuit is connected to the solenoid valve, this control circuit can be manual or the automatic control solenoid valve open or close. Control circuit include a transformer oil face thermometer and one and the digital display temperature controller that the thermometer links to each other, high total low contact of temperature controller links to each other with a temperature -control circuit. Here device easy operation, control by temperature change automation liquid distribution is reliably sensitive, and through the field usage, the cooling has reduced the super temperature operating duration of main change soon during main change full load, has eliminated the hidden danger that arouses insulating reduction because of the super temperature of transformer, has ensured the equipment safe operation.