Abstract: Facing the existence of the power supply dead zone and the coil prone to saturation in conventional current transformers,a new current transformer power supply with a seven-level charge pump circuit is presented based on energy harvesting.The silicon steel material with smaller magnetic permeability is used as the iron core.And the magnetic resistance of iron core magnetic circuit is increased by opening an air gap to make it hard for the saturation of iron core.Then,the charge transferred from the charge pump is stored by the super-capacitor.The power managing module is designed to control the energy-release and power-supply channel.Finally,apower supply prototype is developed and tested by taking wireless temperature measuring module and GPRS module controlled by low-power-consumption singlechip as the load.Experimental results show that the power supply prototype is able to provide sufficient energy when the power transmission line current is1 A.Compared with the current transformer power supply with a secondary winding of 1 500 turns,the power supply designed with a secondary winding of 500 turns has a better performance when the power transmission line current is small.