The utility model relates to the technical field of a transformer, and provides a temperature measuring device of a transformer winding. The temperature measuring device comprises a master control chip, a winding temperature analog display circuit connected with an output control circuit, and an isolation conversion circuit, the output control circuit and the debugging circuit which are connected with the master control chip. The debugging circuit comprises a storage unit. The storage unit prestores a copper oil temperature difference curve of a transformer to be detected, a rated capacity, rated voltage, and a rated current ratio of a current transformer. The isolation conversion circuit comprises an oil surface temperature isolation conversion circuit, a secondary current isolation conversion circuit and an actual heating current isolation conversion circuit which independent from each other and are connected with the master control chip. The temperature measuring device of the transformer winding further comprises an accurate heating current feedback circuit, and the actual heating current feedback circuit is connected with the winding temperature analog display circuit and the actual heating current isolation conversion circuit. The temperature measuring device of the transformer winding can measure and display a quite accurate winding temperature and prolongs the life of the transformer.