In view of the feed dead zone using the current transformer as power source，a current transformer power supply scheme for low current power line is proposed.A circuit model for power supply is developed based on the electromagnetic induction theory，and the relationship between the output power，output voltage，load condition，magnetic coil turns，and core parameter is analyzed.Silicon steel with highly saturated magnetic flux density is selected as the magnetic core.Then，a five-level charge pump circuit，an energy harvesting circuit and a power management circuit each are designed.Finally，power supply equipment is developed based on the scheme aforementioned，and tested using the wireless temperature measuring module as the load.Experimental test shows that the power supply provides stable outputs with no saturation and low heat consumption when the bus current is 1～1000 A.