Measuring transformer ratio with transformer ratio bridge, the operation process is tedious and the measuring scope is narrow, which can’t meet the requirements of modern measurement with fast rhythm and high efficiency. To this end, a new generation transformer ratio group tester is developed by using modern electronic technology. It is small in size, light in weight, accurate and stable. It uses large screen display, menu operation, friendly interface. Change ratio group can be measured in one time. This instrument is an ideal testing instrument for power industry.