The higher the magnetic permeability of the transformer core, the smaller the measurement error, the higher the accuracy. Low safe turns and small ratio requirements, cold-rolled silicon steel is not up to the measurement accuracy and permalloy alloy core because of saturation magnetic induction strength is low and the high cost of use is greatly restricted. Nano amorphous alloy transformer iron core for magnetic properties of high permeability, high saturation magnetic induction and low cost excellent, which is applied widely in 0.2, 02, accuracy of 0.1 grade precision current transformer, epoxy potting bushing type current transformer, oil immersed switchgear, low, medium and high voltage switchgear, power system, power system, relay protection, electric can monitoring device.