For power systems, transformers are the core equipment in the system, so the long-term and reliable operation of the transformer is related to the stability and reliability of the entire system. The DC resistance of a transformer is a must-test project in the manufacturing of semi-finished products and finished products for factory tests, installation, handover tests and power department preventive tests. It can effectively discover manufacturing defects such as material selection, welding, loose connection parts, lack of strands, and broken wires of the transformer coil and hidden dangers after operation. In order to meet the needs of rapid measurement of DC resistance of transformers, our company has developed a DC resistance tester for transformers using its own technical advantages. This instrument is a new generation of rapid tester integrating magnetic assist method testing, three-phase testing (Yn, Y, △) and demagnetization functions. It is an ideal device for measuring the DC resistance of large power transformers. The screen uses a true color large screen high-resolution LCD display, touch and shuttle knob, for easy on-site use. It has Chinese menu prompt function, easy and intuitive operation, completes all direct resistance test items in one wiring, fast test speed, high accuracy and wide range.