The product is a ground resistance test instrument designed and manufactured for on-site measurement of ground resistance, soil resistivity, ground voltage, ground wire leakage current, AC current, DC resistance, etc., based on the new lightning ground resistance test standard. The test current is up to 20 mA. The latest digital processing technology is adopted for precise 4-wire, 3-wire, simple 2-wire, selection, and double-clamp measurement of ground resistance. The large-diameter current clamp design can measure the ground system using large ground lead wires. It can flexibly and accurately measure the arbitrary ground resistance values of single point and mesh grounding under various complex grounding conditions. When measuring parallel grounding, no parallel grounding electrodes need to be disconnected, which greatly increases the convenience of measurement. The FFT (Fast Fourier Transform) and AFC (Automatic Frequency Control) technologies are introduced, which have unique anti-interference ability and environmental adaptability and strong repeatability. It is widely used in power, telecommunications, meteorology, oil fields, construction, lightning protection and industrial electrical equipment for measuring ground resistance, soil resistivity, ground voltage, AC current, and leakage current.