The utility model relates to an electronic tag of an instrument transformer. The instrument transformer may be a current transformer and a voltage transformer; the electronic tag comprises a tag body, an RFID tag cavity and a tag rear cover arranged on the instrument transformer; the tag body, the RFID tag cavity and the tag rear cover are sequentially distributed and are bonded together through ultrasonic waves; the tag body is provided with a groove for accommodating the RFID tag cavity and the rear cover in a stacked manner; the height of the groove is 1mm; the length of the tag body is 60mm, and the width of the tag body is 38mm, and the height of the tag body is 2mm; the length of the RFID tag cavity is 40mm, and the width of the RFID tag cavity is 18mm, and the height of the RFID tag cavity is 0.3mm; the length of the back cover is 39.5mm, and the width of the back cover is 17.5mm, and the height of the back cover is 0.7mm; and the tag body and the rear cover are made of polyphenylene sulfide and glass fibers. With the electronic tag of the utility model adopted, instrument transformers can recognize each other; and man-made errors can be decreased, and the problem of substituting nameplates stealthily can be solved; and labor can be saved, and operation is simple.