The traditional ammeter is inconvenient to carry, wasting a lot of manpower and material resources and low productivity. The size of the high voltage current clamp jaw is small (at present, the size of 10kV/35kV HP tongs in the market is three kinds of diameter of 33mm, 48mm, and 68mm; the traditional high voltage leakage clamp table iron core is not well closed, which leads to low service life and no test; the ordinary high voltage current clamp head has metal core inside and high pressure test insulation. " The performance of the high voltage current clamp tong head is metal iron core, and the cost is too high. Our products have almost zero current tolerance, flexible coil non-magnetic saturation phenomenon, high linearity, and can test large current. The input current can be truly restored by differential and integral of input and output signals, and the current range can be measured from milli level to upper Wan. At the same time, it can solve the problems of large current .