This instrument is an instrument which is specially used for transformer loss parameters and line frequency parameters testing. The instrument has the advantages of ingenious design, excellent performance and powerful functions. The interior adopts advanced multi A/D synchronous sampling and digital signal processing technology, and successfully solves the problem of multi-channel signal synchronous measurement and calculation. The instrument adopts large screen liquid crystal display, Chinese menu prompt, simple operation, equipped with high-speed thermal printer, and has storage function, convenient for data storage and printing. The instrument is small in volume, light in weight, easy to carry and is very convenient to use in the field. It greatly reduces the labor intensity of the experimenters and improves the working efficiency.